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1.	Isaksson, Sofi, et al. (författare) Egfr Amplifications And Mutations In Lung Cancer 2008 Ingår i: Anticancer research. - 1791-7530. ; 28:5C, s. 296-296 Konferensbidrag (refereegranskat)
2.	Staaf, Johan, et al. (författare) Relation between smoking history and gene expression profiles in lung adenocarcinomas 2012 Ingår i: BMC Medical Genomics. - : Springer Science and Business Media LLC. - 1755-8794. ; 5 Tidskriftsartikel (refereegranskat)abstract Background: Lung cancer is the worldwide leading cause of death from cancer. Tobacco usage is the major pathogenic factor, but all lung cancers are not attributable to smoking. Specifically, lung cancer in never-smokers has been suggested to represent a distinct disease entity compared to lung cancer arising in smokers due to differences in etiology, natural history and response to specific treatment regimes. However, the genetic aberrations that differ between smokers and never-smokers' lung carcinomas remain to a large extent unclear. Methods: Unsupervised gene expression analysis of 39 primary lung adenocarcinomas was performed using Illumina HT-12 microarrays. Results from unsupervised analysis were validated in six external adenocarcinoma data sets (n=687), and six data sets comprising normal airway epithelial or normal lung tissue specimens (n=467). Supervised gene expression analysis between smokers and never-smokers were performed in seven adenocarcinoma data sets, and results validated in the six normal data sets. Results: Initial unsupervised analysis of 39 adenocarcinomas identified two subgroups of which one harbored all never-smokers. A generated gene expression signature could subsequently identify never-smokers with 79-100% sensitivity in external adenocarcinoma data sets and with 76-88% sensitivity in the normal materials. A notable fraction of current/former smokers were grouped with never-smokers. Intriguingly, supervised analysis of never-smokers versus smokers in seven adenocarcinoma data sets generated similar results. Overlap in classification between the two approaches was high, indicating that both approaches identify a common set of samples from current/former smokers as potential never-smokers. The gene signature from unsupervised analysis included several genes implicated in lung tumorigenesis, immune-response associated pathways, genes previously associated with smoking, as well as marker genes for alveolar type II pneumocytes, while the best classifier from supervised analysis comprised genes strongly associated with proliferation, but also genes previously associated with smoking. Conclusions: Based on gene expression profiling, we demonstrate that never-smokers can be identified with high sensitivity in both tumor material and normal airway epithelial specimens. Our results indicate that tumors arising in never-smokers, together with a subset of tumors from smokers, represent a distinct entity of lung adenocarcinomas. Taken together, these analyses provide further insight into the transcriptional patterns occurring in lung adenocarcinoma stratified by smoking history.
3.	Andersen, J. R., et al. (författare) Small-x phenomenology - Summary of the 3rd Lund small-x workshop in 2004 2006 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 48:1, s. 53-105 Forskningsöversikt (refereegranskat)abstract A third workshop on small-x physics, within the Small-x Collaboration, was held in Hamburg in May 2004 with the aim of overviewing recent theoretical progress in this area and summarizing the experimental status.
4.	Andersen, JR, et al. (författare) Small-x phenomenology - summary and status 2002 2004 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 35:1, s. 67-98 Forskningsöversikt (refereegranskat)abstract A second workshop on small-x physics, within the Small-x Collaboration, was held in Lund in June 2002 with the aim of over-viewing recent theoretical progress in this area and summarizing the experimental status.
5.	Brunnström, Hans, et al. (författare) Immunohistochemistry in the differential diagnostics of primary lung cancer: an investigation within the southern Swedish lung cancer study. 2013 Ingår i: American Journal of Clinical Pathology. - 1943-7722. ; 140:1, s. 37-46 Tidskriftsartikel (refereegranskat)abstract Objectives: To assess immunohistochemical (IHC) stains differentially expressed between different types of lung cancer. Methods: We evaluated 16 different IHC stains in 209 prospectively included, surgically treated primary lung cancers, including 121 adenocarcinomas, 65 squamous cell carcinomas, 15 large-cell carcinomas, 5 adenosquamous carcinomas, 2 sarcomatoid carcinomas, and 1 small-cell carcinoma, using the tissue microarray technique. Results: Cytokeratin 5 (CK5) and P63 were both positive in 10% or more of the cells in 97% of the squamous cell carcinomas, with the former being positive (<10% of the cells) in only 2 non-squamous cell carcinomas. Thyroid transcription factor 1 (TTF1) and napsin A were positive in 10% or more of the cells in 88% and 87% of the adenocarcinomas, respectively, with 94% of the adenocarcinomas being positive in at least 1 marker. Fifteen percent of the adenocarcinomas were positive for estrogen receptor. Conclusions: CK5, TTF1, and napsin A are sensitive markers for squamous cell carcinoma and adenocarcinoma of the lung.
6.	Isaksson, Sofi, et al. (författare) Characterization Of Non-Small Cell Lung Cancer Using Tiling Resolution Bacterial Artificial Chromosome Microarrays 2008 Ingår i: Anticancer research. - 1791-7530. ; 28:5C, s. 538-538 Konferensbidrag (refereegranskat)
7.	Isaksson, Sofi, et al. (författare) Detecting EGFR alterations in clinical specimens-pitfalls and necessities. 2013 Ingår i: Virchows Archiv: an international journal of pathology. - : Springer Science and Business Media LLC. - 1432-2307. ; 463:6, s. 755-764 Tidskriftsartikel (refereegranskat)abstract We investigated the epidermal growth factor receptor (EGFR) status in early stage lung cancer in Southern Sweden, a population for which there are no previous reports on the EGFR mutation frequency. Three hundred fifty small cell lung cancers, adenocarcinomas (AC), squamous cell carcinomas (SqCC), and large cell carcinomas were analyzed using a combination of techniques for the analysis of protein expression, gene copy numbers, and mutations. Immunohistochemical (IHC) staining with antibodies for the EGFR mutations L858R and del E746-A750 revealed intratumoral heterogeneity and several discrepant cases when compared to mutation-specific polymerase chain reaction (PCR)-based analysis. The frequencies of these two mutations, when considering IHC staining with mutation-specific antibodies in a cohort of 298 cases and subsequent confirmation by PCR, were 10 % in AC and <2 % in SqCC. Furthermore, screening by sequencing of EGFR in a cohort of 52 lung AC and squamous carcinomas demonstrated a more diverse mutation spectrum, not covered by the mutation-specific antibodies. High expression of total EGFR protein was correlated to high gene copy numbers but did not reflect the mutational status of the tumors. We believe that the mutation spectra in a Southern Swedish population is too diverse to be covered by the mutation-specific antibodies, and we also raise some other issues regarding the use of the mutation-specific antibodies, for example concerning heterogeneous expression of the mutated protein, optimal antibody dilution, and discrepancies between staining results and PCR.
8.	Salomonsson, Annette, et al. (författare) Histological specificity of alterations and expression of KIT and KITLG in non-small cell lung carcinoma. 2013 Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257. ; 52:11, s. 1088-1096 Tidskriftsartikel (refereegranskat)abstract Characterization of molecules within important oncogenetic pathways may have future implications for development of therapies and biomarkers in lung cancer. One such target is the tyrosine kinase receptor KIT (c-KIT). We evaluated alterations and expression of KIT and its ligand, KITLG (also known as SCF), in 72 clinical lung tumor specimens of different histologies. Gene copy number, mRNA expression levels, and protein expression were assayed using array-based comparative genomic hybridization, real-time quantitative reverse transcription PCR and immunohistochemistry, respectively. For validation, we investigated copy number alterations and mRNA expression in external microarray data sets of 1,600 and 555 primary lung tumors, respectively. Positivity for KIT staining was most common in large cell neuroendocrine carcinoma (LCNEC) which also showed the highest KIT mRNA expression levels whereas expression was lowest in squamous cell carcinoma (SqCC). KIT mRNA expression levels were higher in KIT immunopositive samples, but expression was not affected by KIT copy numbers. Copy number gains of KIT were significantly more frequent in SqCC compared with adenocarcinoma in our own series and in the 1,600-sample data set. Immunopositivity for both KIT and KITLG in the same tumor was rare except in LCNEC. Our results highlight an increased KIT mRNA expression and frequent KIT immunopositivity in LCNEC but point out a poor correlation between KIT copy numbers and expression in SqCC, perhaps reflecting the existence of a protective mechanism against KIT alterations in this subgroup. © 2013 Wiley Periodicals, Inc.
9.	Staaf, Johan, et al. (författare) Landscape of somatic allelic imbalances and copy number alterations in human lung carcinoma 2013 Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 132:9, s. 2020-2031 Tidskriftsartikel (refereegranskat)abstract Lung cancer is the worldwide leading cause of death from cancer and has been shown to be a heterogeneous disease at the genomic level. To delineate the genomic landscape of copy number alterations, amplifications, loss-of-heterozygosity (LOH), tumor ploidy and copy-neutral allelic imbalance in lung cancer, microarray-based genomic profiles from 2,141 tumors and cell lines including adenocarcinomas (AC, n = 1,206), squamous cell carcinomas (SqCC, n = 467), large cell carcinomas (n = 37) and small cell lung carcinomas (SCLC, n = 88) were assembled from different repositories. Copy number alteration differences between lung cancer histologies were confirmed in 285 unrelated tumors analyzed by BAC array comparative genomic hybridization. Tumor ploidy patterns were validated by DNA flow cytometry analysis of 129 unrelated cases. Eighty-nine recurrent copy number alterations (55 gains, 34 losses) were identified harboring genes with gene expression putatively driven by gene dosage through integration with gene expression data for 496 cases. Thirteen and 26 of identified regions discriminated AC/SqCC and AC/SqCC/SCLC, respectively, while 48 regions harbored recurrent (n > 15) high-level amplifications comprising established and putative oncogenes, differing in frequency and coamplification patterns between histologies. Lung cancer histologies displayed differences in patterns/frequency of copy number alterations, genomic architecture, LOH, copy-neutral allelic imbalance and tumor ploidy, with AC generally displaying less copy number alterations and allelic imbalance. Moreover, a strong association was demonstrated between different types of copy number alterations and allelic imbalances with tumor aneuploidy. In summary, these analyses provide a comprehensive overview of the landscape of genomic alterations in lung cancer, highlighting differences but also similarities between subgroups of the disease.
10.	Aaron, F. D., et al. (författare) A general search for new phenomena at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 674:4-5, s. 257-268 Tidskriftsartikel (refereegranskat)abstract A model-independent search for deviations from the Standard Model prediction is performed using the full e(+/-) p data sample collected by the H1 experiment at HERA. All event topologies involving isolated electrons, photons, muons, neutrinos and jets with transverse momenta above 20 GeV are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A dedicated algorithm is used to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or the invariant mass of final state particles and to quantify their significance. Variables related to angular distributions and energy sharing between final state particles are also introduced to study the final state topologies. No significant deviation from the Standard Model expectation is observed in the phase space covered by this analysis. (C) 2009 Elsevier B.V. All rights reserved.
11.	Aaron, F. D., et al. (författare) A precision measurement of the inclusive ep scattering cross section at HERA 2009 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 64:4, s. 561-587 Tidskriftsartikel (refereegranskat)abstract A measurement of the inclusive deep inelastic neutral current e(+) p scattering cross section is reported in the region of four-momentum transfer squared, 12GeV(2) <= Q(2) <= 150 GeV2, and Bjorken x, 2 x 10(-4) <= x <= 0.1. The results are based on data collected by the H1 Collaboration at the ep collider HERA at positron and proton beam energies of E-e = 27.6 GeV and E-p = 920 GeV, respectively. The data are combined with previously published data, taken at E-p = 820 GeV. The accuracy of the combined measurement is typically in the range of 1.3-2%. A QCD analysis at next-to-leading order is performed to determine the parton distributions in the proton based on H1 data.
12.	Aaron, F. D., et al. (författare) A search for excited neutrinos in e(-) p collisions at HERA 2008 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 663:5, s. 382-389 Tidskriftsartikel (refereegranskat)abstract A search for first generation excited neutrinos is performed using the full e(-) p data sample collected by the HI experiment at HERA at a centre-of-mass energy of 319 GeV, corresponding to a total luminosity of 184 pb(-1). The electroweak decays of excited neutrinos nu* -> nu gamma, v* -> nu Z and nu* -> eW with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for excited neutrino production is found. Mass dependent exclusion limits on nu* production cross sections and on the ratio of the coupling to the compositeness scale f/boolean AND are derived within gauge mediated models. A limit on f/boolean AND A, independent of the relative couplings to the SU(2) and U(1) gauge bosons, is also determined. These limits extend the excluded region to higher masses than has been possible in previous excited neutrino searches. (c) 2008 Elsevier B.V. All rights reserved.
13.	Aaron, F.D., et al. (författare) Charged particle production in high Q^2 deep-inelastic scattering at HERA 2007 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 654:5-6, s. 148-159 Tidskriftsartikel (refereegranskat)abstract The average charged track multiplicity and the normalised distribution of the scaled momentum, xp, of charged final state hadrons are measured in deep-inelastic ep scattering at high Q2 in the Breit frame of reference. The analysis covers the range of photon virtuality Click to view the MathML source. Compared with previous results presented by HERA experiments this analysis has a significantly higher statistical precision and extends the phase space to higher Q2 and to the full range of xp. The results are compared with e+e− annihilation data and with various calculations based on perturbative QCD using different models of the hadronisation process.
14.	Aaron, F. D., et al. (författare) Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA 2012 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:10 Tidskriftsartikel (refereegranskat)abstract A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy root s = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6 % for the most precise points. The combined data cover the range 2.5 < Q(2) < 200 GeV2 in photon virtuality, 0.00035 < x(P) < 0.09 in proton fractional momentum loss, 0.09 < vertical bar t vertical bar < 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < beta < 0.816 in beta = x/x(P), where x is the Bjorken scaling variable.
15.	Aaron, F. D., et al. (författare) Combined measurement and QCD analysis of the inclusive e(+/-)p scattering cross sections at HERA 2010 Ingår i: Journal of High Energy Physics. - 1029-8479. ; :1 Tidskriftsartikel (refereegranskat)abstract A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e(+/-)p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q(2), and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.
16.	Aaron, F. D., et al. (författare) Deeply virtual Compton scattering and its beam charge asymmetry in e(+/-)p collisions at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 681:5, s. 391-399 Tidskriftsartikel (refereegranskat)abstract A measurement of elastic deeply virtual Compton scattering gammap --> gamma p using e(+) p and e(-) p collision data recorded with the HI detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 306 pb(-1), almost equally shared between both beam charges. The cross section is measured as a function of the virtuality Q(2) of the exchanged photon and the centre-of-mass energy W of the gammap system in the kinematic domain 6.5 < Q(2) < 80 GeV2, 30 < W < 140 GeV and \|t\| < 1 GeV2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q(2) and W values and exponential t-slope parameters are derived. Using e(+) p and e(-) p data samples, a beam charge asymmetry is extracted for the first time in the low Biorken x kinematic domain. The observed asymmetry is attributed to the interference between Bethe-Heitler and deeply virtual Compton scattering processes. Experimental results are discussed in the context of two different models, one based on generalised parton distributions and one based on the dipole approach. (C) 2009 Elsevier B.V. All rights reserved.
17.	Aaron, F. D., et al. (författare) Determination of the integrated luminosity at HERA using elastic QED Compton events 2012 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:10 Tidskriftsartikel (refereegranskat)abstract A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep -> e gamma p. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3%. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process.
18.	Aaron, F. D., et al. (författare) Diffractive dijet photoproduction in ep collisions at HERA 2010 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 70:1-2, s. 15-37 Tidskriftsartikel (refereegranskat)abstract Measurements are presented of single and double-differential dijet cross sections in diffractive photoproduction based on a data sample with an integrated luminosity of 47 pb(-1). The events are of the type ep -> eXY, where the hadronic system X contains at least two jets and is separated by a large rapidity gap from the system Y, which consists of a leading proton or low-mass proton excitation. The dijet cross sections are compared with QCD calculations at next-to-leading order and with a Monte Carlo model based on leading order matrix elements with parton showers. The measured cross sections are smaller than those obtained from the next-to-leading order calculations by a factor of about 0.6. This suppression factor has no significant dependence on the fraction x (gamma) of the photon four-momentum entering the hard subprocess. Ratios of the diffractive to the inclusive dijet cross sections are measured for the first time and are compared with Monte Carlo models.
19.	Aaron, F. D., et al. (författare) Diffractive electroproduction of rho and phi mesons at HERA 2010 Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2010:5, s. 1-111 Tidskriftsartikel (refereegranskat)abstract Diffractive electroproduction of rho and phi mesons is measured at HERA with the H1 detector in the elastic and proton dissociative channels. The data correspond to an integrated luminosity of 51 pb(-1). About 10500 rho and 2000 phi events are analysed in the kinematic range of squared photon virtuality 2.5 <= Q(2) <= 60 GeV2, photon-proton centre of mass energy 35 <= W <= 180 GeV and squared four-momentum transfer to the proton vertical bar t vertical bar <= 3 GeV2. The total, longitudinal and transverse cross sections are measured as a function of Q(2), W and vertical bar t vertical bar. The measurements show a transition to a dominantly "hard" behaviour, typical of high gluon densities and small q (q) over bar dipoles, for Q(2) larger than 10 to 20 GeV2. They support flavour independence of the diffractive exchange, expressed in terms of the scaling variable (Q(2) + M-V(2))/4, and proton vertex factorisation. The spin density matrix elements are measured as a function of kinematic variables. The ratio of the longitudinal to transverse cross sections, the ratio of the helicity amplitudes and their relative phases are extracted. Several of these measurements have not been performed before and bring new information on the dynamics of diffraction in a QCD framework. The measurements are discussed in the context of models using generalised parton distributions or universal dipole cross sections.
20.	Aaron, F. D., et al. (författare) Events with an isolated lepton and missing transverse momentum and measurement of W production at HERA 2010 Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2010:3, s. 1-19 Tidskriftsartikel (refereegranskat)abstract A search for events containing an isolated electron or muon and missing trans verse momentum produced in e(+/-)p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb(-1). The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e(+)p data, at large hadronic transverse momentum P-T(X) > 25GeV, a total of 23 events are observed compared to a prediction of 14.0 +/- 1.9. The total single W boson production cross section is measured as 1.06 +/- 0.16 (stat.) +/- 0.07 (sys.) pb, in agreement with an Standard Model (SM) expectation of 1.26 +/- 0.19 pb.
21.	Aaron, F. D., et al. (författare) Events with isolated leptons and missing transverse momentum and measurement of W production at HERA 2009 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 64:2, s. 251-271 Tidskriftsartikel (refereegranskat)abstract Events with high energy isolated electrons, muons or tau leptons and missing transverse momentum are studied using the full e(+/-)p data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb(-1). Within the Standard Model, events with isolated leptons and missing transverse momentum mainly originate from the production of single W bosons. The total single W boson production cross section is measured as 1.14 +/- 0.25 (stat.) +/- 0.14 (sys.) pb, in agreement with the Standard Model expectation. The data are also used to establish limits on the WW gamma gauge couplings and for a measurement of the W boson polarisation.
22.	Aaron, F. D., et al. (författare) Inclusive deep inelastic scattering at high Q(2) with longitudinally polarised lepton beams at HERA 2012 Ingår i: Journal of High Energy Physics. - 1029-8479. ; :9 Tidskriftsartikel (refereegranskat)abstract Inclusive e(+/-)p single and double differential cross sections for neutral and charged current deep inelastic scattering processes are measured with the H1 detector at HERA. The data were taken at a centre-of-mass energy of root s = 319 GeV with a total integrated luminosity of 333.7 pb(-1) shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative four-momentum transfer squared, Q(2), between 60 and 50 000GeV(2), and Bjorken x between 0.0008 and 0.65. The measurements are combined with earlier published unpolarised H1 data to improve statistical precision and used to determine the structure function xF(3)(gamma Z). A measurement of the neutral current parity violating structure function F-2(gamma Z) is presented for the first time. The polarisation dependence of the charged current total cross section is also measured. The new measurements are well described by a next-to-leading order QCD fit based on all published H1 inclusive cross section data which are used to extract the parton distribution functions of the proton.
23.	Aaron, F. D., et al. (författare) Inclusive measurement of diffractive deep-inelastic scattering at HERA 2012 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:7 Tidskriftsartikel (refereegranskat)abstract The diffractive process ep -> eXY, where Y denotes a proton or its low mass excitation with M-Y < 1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3 <= Q(2) <= 1600 GeV2, the square of the fourmomentum transfer at the proton vertex vertical bar t vertical bar < 1.0 GeV2 and the longitudinal momentum fraction of the incident proton carried by the colourless exchange x(P) < 0.05. Triple differential cross sections are measured as a function of x(P), Q(2) and beta = x/x(P) where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y. High statistics measurements covering the data taking periods 1999-2000 and 2004-2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The combined data represent a factor between three and thirty increase in statistics with respect to the previously published results. The measurements are compared with predictions from NLO QCD calculations based on diffractive parton densities and from a dipole model. The proton vertex factorisation hypothesis is tested.
24.	Aaron, F. D., et al. (författare) Inclusive photoproduction of rho(0), K(0) and phi mesons at HERA H1 Collaboration 2009 Ingår i:* Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 673:2, s. 119-126 Tidskriftsartikel (refereegranskat)abstract Inclusive non-diffractive photoproduction of rho(770)(0), K*(892)(0) and phi(1020) mesons is investigated with the H1 detector in ep collisions at HERA. The corresponding average gamma p centre-of-mass energy is 210 GeV. The mesons are measured in the transverse momentum range 0.5 < p(T) < 7 GeV and the rapidity range vertical bar y(lab)vertical bar < 1. Differential cross sections are presented as a function of transverse momentum and rapidity, and are compared to the predictions of hadroproduction models. (C) 2009 Elsevier B.V. All rights reserved.
25.	Aaron, F. D., et al. (författare) Jet production in ep collisions at low Q(2) and determination of alpha(s) 2010 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 67:1-2, s. 1-24 Tidskriftsartikel (refereegranskat)abstract The production of jets is studied in deep-inelastic e(+) p scattering at low negative four momentum transfer squared 5 < Q(2) < 100 GeV2 and at inelasticity 0.2 < y < 0.7 using data recorded by the H1 detector at HERA in the years 1999 and 2000, corresponding to an integrated luminosity of 43.5 pb(-1). Inclusive jet, 2-jet and 3-jet cross sections as well as the ratio of 3-jet to 2-jet cross sections are measured as a function of Q(2) and jet transverse momentum. The 2-jet cross section is also measured as a function of the proton momentum fraction xi. The measurements are well described by perturbative quantum chromodynamics at next-to-leading order corrected for hadronisation effects and are subsequently used to extract the strong coupling as.
26.	Aaron, F. D., et al. (författare) Measurement of beauty photoproduction near threshold using di-electron events with the H1 detector at HERA 2012 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:10 Tidskriftsartikel (refereegranskat)abstract The cross section for ep -> eb (b) over barX in photoproduction is measured with the H1 detector at the ep-collider HERA. The decay channel b (b) over bar -> eeX' is selected by identifying the semi-electronic decays of the b-quarks. The total production cross section is measured in the kinematic range given by the photon virtuality Q(2) <= 1 GeV2, the inelasticity 0.05 <= y <= 0.65 and the pseudorapidity of the b-quarks vertical bar eta(b)vertical bar, vertical bar eta((b) over bar)vertical bar <= 2. The differential production cross section is measured as a function of the average transverse momentum of the beauty quarks < P-T(b)> down to the threshold. The results are compared to next-to-leading-order QCD predictions.
27.	Aaron, F. D., et al. (författare) Measurement of charm and beauty jets in deep inelastic scattering at HERA 2011 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:1 Tidskriftsartikel (refereegranskat)abstract Measurements of cross sections for events with charm and beauty jets in deep inelastic scattering at HERA are presented. Events with jets of transverse energy E-T(jet) > 6 GeV and pseudorapidity - 1.0 < eta(jet) < 1.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q(2) > 6 GeV2 and inelasticity variable 0.07 < y < 0.625. Measurements are also made requiring a jet in the Breit frame with E-T(*jet) > 6 GeV. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb(-1). The numbers of charm and beauty jets are determined using variables reconstructed using the H1 vertex detector with which the impact parameters of the tracks to the primary vertex and the position of secondary vertices are measured. The measurements are compared with QCD predictions and with previous measurements where heavy flavours are identified using muons.
28.	Aaron, F. D., et al. (författare) Measurement of D(+/-) meson production and determination of F-2(c(c)over-bar) at low Q(2) in deep-inelastic scattering at HERA 2011 Ingår i:* European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:10 Tidskriftsartikel (refereegranskat)abstract Inclusive production of D* mesons in deep-inelastic ep scattering at HERA is studied in the range 5 < Q(2) < 100 GeV2 of the photon virtuality and 0.02 < y < 0.7 of the inelasticity of the scattering process. The observed phase space for the D* meson is (pT) (D) > 1.25 GeV and \|eta( D)\| < 1.8. The data sample corresponds to an integrated luminosity of 348 pb(-1) collected with the H1 detector. Single and double differential cross sections are measured and the charm contribution F-2(c (c) over bar) to the proton structure function F-2 is determined. The results are compared to perturbative QCD predictions at next-to-leading order implementing different schemes for the charm mass treatment and with Monte Carlo models based on leading order matrix elements with parton showers.
29.	Aaron, F. D., et al. (författare) Measurement of diffractive scattering of photons with large momentum transfer at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 672:3, s. 219-226 Tidskriftsartikel (refereegranskat)abstract The first measurement of diffractive scattering of quasi-real photons with large momentum transfer gamma p -> gamma Y, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q(2) < 0.01 GeV2. Single differential cross sections are Measured as a function of W, the incident photon-proton centre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175 < W < 247 GeV and 4 < \|t\| < 36 GeV2. The W dependence is well described by a model based on perturbative QCD using a leading logarithmic approximation of the BFKL evolution. The measured \|t\| dependence is harder than that predicted by the model and those observed in exclusive vector meson production. (C) 2009 Published by Elsevier B.V.
30.	Aaron, F. D., et al. (författare) Measurement of dijet production in diffractive deep-inelastic scattering with a leading proton at HERA 2012 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:4 Tidskriftsartikel (refereegranskat)abstract The cross section of diffractive deep-inelastic scattering ep -> eXp is measured, where the system X contains at least two jets and the leading final state proton is detected in the H1 Forward Proton Spectrometer. The measurement is performed for fractional proton longitudinal momentum loss x(P) < 0.1 and covers the range 0.1 < vertical bar t vertical bar < 0.7 GeV2 in squared four-momentum transfer at the proton vertex and 4 < Q(2) < 110 GeV2 in photon virtuality. The differential cross sections extrapolated to vertical bar t vertical bar < 1 GeV2 are in agreement with next-to-leading order QCD predictions based on diffractive parton distribution functions extracted from measurements of inclusive and dijet cross sections in diffractive deep-inelastic scattering. The data are also compared with leading order Monte Carlo models.
31.	Aaron, F. D., et al. (författare) Measurement of inclusive and dijet D* meson cross sections in photoproduction at HERA 2012 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:5 Tidskriftsartikel (refereegranskat)abstract The inclusive photoproduction of D* mesons and of D-tagged dijets is investigated with the H1 detector at the ep collider HERA. The kinematic region covers small photon virtualities Q(2) < 2 GeV2 and photon-proton centre-of-mass energies of 100< W-gamma p < 285 GeV. Inclusive D meson differential cross sections are measured for central rapidities vertical bar eta(D)vertical bar < 1.5 and transverse momenta p(T) (D) > 1.8 GeV. The heavy quark production process is further investigated in events with at least two jets with transverse momentum p(T) (jet) > 3.5 GeV each, one containing the D* meson. Differential cross sections for D-tagged dijet production and for correlations between the jets are measured in the range vertical bar eta(D)vertical bar < 1.5 and p(T) (D*) > 2.1 GeV. The results are compared with predictions from Monte Carlo simulations and next-to-leading order perturbative QCD calculations.
32.	Aaron, F. D., et al. (författare) Measurement of isolated photon production in deep-inelastic scattering at HERA 2008 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 54:3, s. 371-387 Tidskriftsartikel (refereegranskat)abstract The production of isolated photons in deep-inelastic scattering ep -> e gamma X is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 4 < Q(2)< 150 GeV2 and a mass of the hadronic system W-X > 50 GeV. The analysis is based on a total integrated luminosity of 227 pb(-1). The production cross section of isolated photons with a transverse energy in the range 3 < E-T(gamma)< 10 GeV and pseudorapidity range -1.2
33.	Aaron, F. D., et al. (författare) Measurement of photon production in the very forward direction in deep-inelastic scattering at HERA 2011 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:10 Tidskriftsartikel (refereegranskat)abstract The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 126 pb(-1). The analysis covers the range of negative four momentum transfer squared at the positron vertex 6 < Q(2) < 100 GeV2 and inelasticity 0.05 < y < 0.6. Cross sections are measured for the most energetic photon with pseudorapidity eta > 7.9 as a function of its transverse momentum p(T)(lead) and longitudinal momentum fraction of the incoming proton x(L)(lead). In addition, the cross sections are studied as a function of the sum of the longitudinal momentum fraction x(L)(sum) L of all photons in the pseudorapidity range. > 7.9. The cross sections are normalised to the inclusive deep-inelastic scattering cross section and compared to the predictions of models of deep-inelastic scattering and models of the hadronic interactions of high energy cosmic rays.
34.	Aaron, F. D., et al. (författare) Measurement of the azimuthal correlation between the most forward jet and the scattered positron in deep-inelastic scattering at HERA 2012 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:3 Tidskriftsartikel (refereegranskat)abstract Deep-inelastic positron-proton scattering events at low photon virtuality, Q(2), with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples, differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, Delta phi, between the forward jet and the scattered positron in bins of the rapidity distance, Y, between them. The data are compared to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations in order to test the sensitivity to QCD evolution mechanisms.
35.	Aaron, F. D., et al. (författare) Measurement of the charm and beauty structure functions using the H1 vertex detector at HERA 2010 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 65:1-2, s. 89-109 Tidskriftsartikel (refereegranskat)abstract Inclusive charm and beauty cross sections are measured in e (-) p and e (+) p neutral current collisions at HERA in the kinematic region of photon virtuality 5a parts per thousand currency signQ (2)a parts per thousand currency sign2000 GeV2 and Bjorken scaling variable 0.0002a parts per thousand currency signxa parts per thousand currency sign0.05. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb(-1). The numbers of charm and beauty events are determined using variables reconstructed by the H1 vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions.
36.	Aaron, F. D., et al. (författare) Measurement of the cross section for diffractive deep-inelastic scattering with a leading proton at HERA 2011 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:3 Tidskriftsartikel (refereegranskat)abstract The cross section for the diffractive deep-inelastic scattering process ep -> eXp is measured, with the leading final state proton detected in the H1 Forward Proton Spectrometer. The data sample covers the range x(P) < 0.1 in fractional proton longitudinal momentum loss, 0.1 < vertical bar t vertical bar < 0.7 GeV2 in squared four-momentum transfer at the proton vertex and 4 < Q(2) < 700 GeV2 in photon virtuality. The cross section is measured four-fold differentially in t, x(P), Q2 and beta = x/x(P), where x is the Bjorken scaling variable. The t and x(P) dependences are interpreted in terms of an effective pomeron trajectory and a sub-leading exchange. The data are compared with perturbative QCD predictions at next-to-leading order based on diffractive parton distribution functions previously extracted from complementary measurements of inclusive diffractive deep-inelastic scattering. The ratio of the diffractive to the inclusive ep cross section is studied as a function of Q(2), beta and x(P).
37.	Aaron, F. D., et al. (författare) Measurement of the D(+/-) meson production cross section and F-2(c(c)over-bar) at high Q(2) in ep scattering at HERA 2010 Ingår i:* Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 686:2-3, s. 91-100 Tidskriftsartikel (refereegranskat)abstract The inclusive production of D(+/-)(2010) mesons in deep-inelastic e(+/-)p scattering is measured in the kinematic region of photon virtuality 100 < Q(2) < 1000 GeV2 and inelasticity 002 < y < 0 7 Single and double differential cross sections for inclusive D meson production are measured in the visible range defined by vertical bar eta(D)vertical bar < 1 5 and p(gamma)(D) > 1 5 GeV The data were collected by the H1 experiment during the period from 2004 to 2007 and correspond to an integrated luminosity of 351 pb(-1) The charm contribution. F-2(c (c) over bar), to the proton structure function F-2 is determined. The measurements are compared with QCD predictions. (C) 2010 Elsevier B V All rights reserved
38.	Aaron, F. D., et al. (författare) Measurement of the diffractive longitudinal structure function F(L)(D) at HERA 2011 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:12 Tidskriftsartikel (refereegranskat)abstract First measurements are presented of the diffractive cross section sigma(ep) -> eXY at centre-of-mass energies root s of 225 and 252 GeV, together with a precise new measurement at root s of 319 GeV, using data taken with the H1 detector in the years 2006 and 2007. Together with previous H1 data at root s of 301 GeV, the measurements are used to extract the diffractive longitudinal structure function F(L)(D) in the range of photon virtualities 4.0 <= Q(2) <= 44.0 GeV(2) and fractional proton longitudinal momentum loss 5 x 10(-4) <= x(P) <= 3 x 10(-3). The measured F(L)(D) is compared with leading twist predictions based on diffractive parton densities extracted in NLO QCD fits to previous measurements of diffractive Deep-Inelastic Scattering and with a model which additionally includes a higher twist contribution derived from a colour dipole approach. The ratio of the diffractive cross section induced by longitudinally polarised photons to that for transversely polarised photons is extracted and compared with the analogous quantity for inclusive Deep-Inelastic Scattering.
39.	Aaron, F. D., et al. (författare) Measurement of the inclusive e(+/-) p scattering cross section at high inelasticity y and of the structure function F-L 2011 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:3 Tidskriftsartikel (refereegranskat)abstract A measurement is presented of the inclusive neutral current e(+/-) p scattering cross section using data collected by the H1 experiment at HERA during the years 2003 to 2007 with proton beam energies E-p of 920, 575, and 460 GeV. The kinematic range of the measurement covers low absolute four-momentum transfers squared, 1.5 GeV2 < Q(2) < 120 GeV2, small values of Bjorken x, 2.9 . 10(-5) < x < 0.01, and extends to high inelasticity up to y = 0.85. The structure function F-L is measured by combining the new results with previously published H1 data at E-p = 920 GeV and E-p = 820 GeV. The new measurements are used to test several phenomenological and QCD models applicable in this low Q(2) and low x kinematic domain.
40.	Aaron, F. D., et al. (författare) Measurement of the inclusive ep scattering cross section at low Q (2) and x at HERA 2009 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 63:4, s. 625-678 Tidskriftsartikel (refereegranskat)abstract A measurement of the inclusive ep scattering cross section is presented in the region of low momentum transfers, 0.2 GeV2 a parts per thousand currency signQ (2)a parts per thousand currency sign12 GeV2, and low Bjorken x, 5a <...10(-6)a parts per thousand currency signxa parts per thousand currency sign0.02. The result is based on two data sets collected in dedicated runs by the H1 Collaboration at HERA at beam energies of 27.6 GeV and 920 GeV for positrons and protons, respectively. A combination with data previously published by H1 leads to a cross section measurement of a few percent accuracy. A kinematic reconstruction method exploiting radiative ep events extends the measurement to lower Q (2) and larger x. The data are compared with theoretical models which apply to the transition region from photoproduction to deep inelastic scattering.
41.	Aaron, F. D., et al. (författare) Measurement of the proton structure function F-L(x, Q(2)) at low x 2008 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 665:4, s. 139-146 Tidskriftsartikel (refereegranskat)abstract A first measurement is reported of the longitudinal proton structure function FL(X, Q(2)) at the ep collider HERA. It is based on inclusive deep inelastic e(+)p scattering cross section measurements with a positron beam energy of 27.5 GeV and proton beam energies of 920, 575 and 460 GeV. Employing the energy dependence of the cross section, FL is measured in a range of squared four-momentum transfers 12 <= Q2 <=, 90 GeV2 and low Bjorken x 0.00024 <= x <= 0.0036. The F-L values agree with higher order QCD calculations based on parton densities obtained using cross section data previously measured at HERA. (C) 2008 Elsevier B.V. All rights reserved.
42.	Aaron, F. D., et al. (författare) Multi-lepton production at high transverse momenta in ep collisions at HERA 2008 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 668:4, s. 268-276 Tidskriftsartikel (refereegranskat)abstract Processes leading to a final state with at least two high transverse momentum leptons (electrons or muons) are studied using the full e(+/-) p data sample collected by the H1 experiment at HERA. The data correspond to an integrated luminosity of 463 pb(-1). Di-lepton and tri-lepton event classes are investigated. Cross sections of the production of e(+)e(-) and mu(+)mu(-) pairs are derived in a restricted phase space dominated by photon-photon collisions. In general, good agreement is found with Standard Model predictions. Events are observed with a total scalar sum of lepton transverse momenta above 100 GeV where the Standard Model expectation is low. In this region, combining di-lepton and tri-lepton classes, five events are observed in e(+) p collisions, compared to a Standard Model expectation of 0.96 +/- 0.12, while no such event is observed in e(-) p data for 0.64 +/- 0.09 expected. (C) 2008 Elsevier B.V. All rights reserved.
43.	Aaron, F. D., et al. (författare) Multi-leptons with high transverse momentum at HERA 2009 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :10 Tidskriftsartikel (refereegranskat)abstract Events with at least two high transverse momentum leptons (electrons or muons) are studied using the H1 and ZEUS detectors at HERA with an integrated luminosity of 0.94 fb(-1). The observed numbers of events are in general agreement with the Standard Model predictions. Seven di- and tri-lepton events are observed in e(+)p collision data with a scalar sum of the lepton transverse momenta above 100 GeV while 1.94 +/- 0.17 events are expected. Such events are not observed in e(-)p collisions for which 1.19 +/- 0.12 are predicted. Total visible and differential di-electron and di-muon photoproduction cross sections are extracted in a restricted phase space dominated by photon-photon collisions.
44.	Aaron, F. D., et al. (författare) Observation of the hadronic final state charge asymmetry in high Q(2) deep-inelastic scattering at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 681:2, s. 125-133 Tidskriftsartikel (refereegranskat)abstract A first measurement is presented of the charge asymmetry in the hadronic final state from the hard interaction in deep-inelastic ep neutral current scattering at HERA. The measurement is performed in the range of negative squared four momentum transfer 100 < Q(2) < 8000 GeV2. The difference between the event normalised distributions of the scaled momentum, x(p), for positively and negatively charged particles, measured in the current region of the Breit frame, is studied together with its evolution as a function of Q. The results are compared to Monte Carlo models at the hadron and parton levels. (C) 2009 Elsevier B.V. All rights reserved.
45.	Aaron, F. D., et al. (författare) Prompt photons in photoproduction at HERA 2010 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 66:1-2, s. 17-33 Tidskriftsartikel (refereegranskat)abstract The production of prompt photons is measured in the photoproduction regime of electron-proton scattering at HERA. The analysis is based on a data sample corresponding to a total integrated luminosity of 340 pb(-1) collected by the H1 experiment. Cross sections are measured for photons with transverse momentum and pseudorapidity in the range 6< E-T(gamma) < 15 GeV and -1.0< eta(gamma) < 2.4, respectively. Cross sections for events with an additional jet are measured as a function of the transverse energy and pseudorapidity of the jet, and as a function of the fractional momenta x(gamma) and x(p) carried by the partons entering the hard scattering process. The correlation between the photon and the jet is also studied. The results are compared with QCD predictions based on the collinear and on the k(T) factorization approaches.
46.	Aaron, F. D., et al. (författare) Search for contact interactions in e(+/-)p collisions at HERA H1 Collaboration 2011 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 705:1-2, s. 52-58 Tidskriftsartikel (refereegranskat)abstract A search for physics beyond the Standard Model in neutral current deep inelastic scattering at high negative four-momentum transfer squared Q(2) is performed in e(+/-)p collisions at HERA. The differential cross section d sigma/dQ(2), measured using the full H1 data sample corresponding to an integrated luminosity of 446 pb(-1), is compared to the Standard Model prediction. No significant deviation is observed. Limits on various models predicting new phenomena at high Q(2) are derived. For general four-fermion eeqq contact interaction models, lower limits on the compositeness scale A are set in the range 3.6 TeV to 7.2 TeV. Leptoquarks with masses M-LQ and couplings lambda are constrained to M-LQ/lambda > 0.41-1.86 TeV and limits on squarks in R-parity violating supersymmetric models are derived. A lower limit on the gravitational scale in 4 + n dimensions of M-S > 0.9 TeV is established for low-scale quantum gravity effects in models with large extra dimensions. For the light quark radius an upper bound of R-q < 0.65 . 10(-18) m is determined. (C) 2011 Elsevier B.V. All rights reserved.
47.	Aaron, F. D., et al. (författare) Search for excited electrons in ep collisions at HERA 2008 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 666:2, s. 131-139 Tidskriftsartikel (refereegranskat)abstract A search for excited electrons is performed using the full e(+/-) p data sample collected by the HI experiment at HERA, corresponding to a total luminosity of 475 pb(-1). The electroweak decays of excited electrons e* -> e gamma, e* -> eZ and e* -> vW with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for excited electron production is found. Mass dependent exclusion limits on e* production cross sections and on the ratio f/Lambda of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited electron searches. The e* production via contact interactions is also addressed for the first time in ep collisions. (C) 2008 Elsevier B.V. All rights reserved.
48.	Aaron, F. D., et al. (författare) Search for excited quarks in ep collisions at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 678:4, s. 335-343 Tidskriftsartikel (refereegranskat)abstract A search for excited quarks is performed using the full e(+/-)p data sample collected by the HI experiment at HERA, corresponding to a total integrated luminosity of 475 pb(-1). The electroweak decays of excited quarks q* -> q gamma. q* -> qZ and q* - qW with Subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q* production cross sections and on the ratio f/Lambda of the coupling to the compositeness scale are derived Within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches. (C) 2009 Elsevier B.V. All rights reserved.
49.	Aaron, F. D., et al. (författare) Search for first generation leptoquarks in ep collisions at HERA 2011 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 704:5, s. 388-396 Tidskriftsartikel (refereegranskat)abstract A search for first generation scalar and vector leptoquarks produced in ep collisions is performed by the H1 experiment at HERA. The full H1 data sample is used in the analysis, corresponding to an integrated luminosity of 446 pb(-1). No evidence for the production of leptoquarks is observed in final states with a large transverse momentum electron or with large missing transverse momentum, and constraints on leptoquark models are derived. For leptoquark couplings of electromagnetic strength lambda = 0.3, first generation leptoquarks with masses up to 800 GeV are excluded at 95% confidence level. (C) 2011 Elsevier B.V. All rights reserved.
50.	Aaron, F. D., et al. (författare) Search for lepton flavour violation at HERA 2011 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 701:1, s. 20-30 Tidskriftsartikel (refereegranskat)abstract A search for second and third generation scalar and vector leptoquarks produced in ep collisions via the lepton flavour violating processes ep -> mu X and ep -> tau X is performed by the H1 experiment at HERA. The full data sample taken at a centre-of-mass energy root s = 319 GeV is used for the analysis, corresponding to an integrated luminosity of 245 pb(-1) of e(+)p and 166 pb(-1) of e(-)p collision data. No evidence for the production of such leptoquarks is observed in the H1 data. Leptoquarks produced in e(+/-)p collisions with a coupling strength of lambda = 0.3 and decaying with the same coupling strength to a muon-quark pair or a tau-quark pair are excluded at 95% confidence level up to leptoquark masses of 712 GeV and 479 GeV, respectively. (C) 2011 Elsevier B.V. All rights reserved.

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