| 1. |
- Abulaiti, Yiming, et al.
(författare)
-
Measurement of exclusive gamma gamma -> W+W- production and search for exclusive Higgs boson production in pp collisions at root s=8 TeV using the ATLAS detector
- 2016
-
Ingår i: Physical Review D. - 2470-0010 .- 1550-7998 .- 1550-2368. ; 94:3
-
Tidskriftsartikel (refereegranskat)abstract
- Searches for exclusively produced W boson pairs in the process pp(gamma gamma) -> pW(+) W- p and an exclusively produced Higgs boson in the process pp(gg) -> pHp have been performed using e(+/-) mu(-/+) final states. These measurements use 20.2 fb(-1) of pp collisions collected by the ATLAS experiment at a center-of-mass energy root s = 8 TeV at the LHC. Exclusive production of W+ W- consistent with the Standard Model prediction is found with 3.0 sigma significance. The exclusive W+ W- production cross section is determined to be sigma(gamma gamma -> W+ W- -> e(+/-) mu(-/+) X) = 6.9 +/- 2.2(stat) +/- 1.4(sys) fb, in agreement with the Standard Model prediction. Limits on anomalous quartic gauge couplings are set at 95% confidence level as -1.7 x 10(-6) < a(0)(W) / Lambda(2) < 1.7 x 10(-6) GeV-2 and -6.4 x 10(-6) < a(C)(W) / Lambda(2) < 6.3 x 10(-6) GeV-2. A 95% confidence-level upper limit on the total production cross section for an exclusive Higgs boson is set to 1.2 pb.
|
|
| 2. |
- Abulaiti, Yiming, et al.
(författare)
-
Measurement of the differential cross-section of highly boosted top quarks as a function of their transverse momentum in root s=8 TeV proton-proton collisions using the ATLAS detector
- 2016
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 1550-7998 .- 1550-2368. ; 93:3
-
Tidskriftsartikel (refereegranskat)abstract
- The differential cross-section for pair production of top quarks with high transverse momentum is measured in 20.3 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV. The measurement is performed for t (t) over bar events in the lepton + jets channel. The cross-section is reported as a function of the hadronically decaying top quark transverse momentum for values above 300 GeV. The hadronically decaying top quark is reconstructed as an anti-k(t) jet with radius parameter R = 1.0 and identified with jet substructure techniques. The observed yield is corrected for detector effects to obtain a cross-section at particle level in a fiducial region close to the event selection. A parton-level cross-section extrapolated to the full phase space is also reported for top quarks with transverse momentum above 300 GeV. The predictions of a majority of next-to-leading-order and leading-order matrix-element Monte Carlo generators are found to agree with the measured cross-sections.
|
|
| 3. |
- Abulaiti, Yiming, et al.
(författare)
-
Measurement of top quark pair differential cross sections in the dilepton channel in pp collisions at root s=7 and 8 TeV with ATLAS
- 2016
-
Ingår i: Physical Review D. - : Springer. - 2470-0010 .- 2470-0029. ; 94:9
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of normalized differential cross sections of top quark pair (t (t) over bar) production are presented as a function of the mass, the transverse momentum and the rapidity of the t (t) over bar system in proton-proton collisions at center-of-mass energies of root s = 7 and 8 TeV. The data set corresponds to an integrated luminosity of 4.6 fb(-1) at 7 TeV and 20.2 fb(-1) at 8 TeV, recorded with the ATLAS detector at the Large Hadron Collider. Events with top quark pair signatures are selected in the dilepton final state, requiring exactly two charged leptons and at least two jets with at least one of the jets identified as likely to contain a b hadron. The measured distributions are corrected for detector effects and selection efficiency to cross sections at the parton level. The differential cross sections are compared with different Monte Carlo generators and theoretical calculations of t (t) over bar production. The results are consistent with the majority of predictions in a wide kinematic range.
|
|
| 4. |
- Abulaiti, Yiming, et al.
(författare)
-
Search for dark matter produced in association with a Higgs boson decaying to two bottom quarks in pp collisions at root s=8 TeV with the ATLAS detector
- 2016
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 1550-7998 .- 1550-2368. ; 93:7
-
Tidskriftsartikel (refereegranskat)abstract
- This article reports on a search for dark matter pair production in association with a Higgs boson decaying to a pair of bottom quarks, using data from 20.3 fb(-1) of pp collisions at a center-of-mass energy of 8 TeV collected by the ATLAS detector at the LHC. The decay of the Higgs boson is reconstructed as a high-momentum b (b) over bar system with either a pair of small-radius jets, or a single large-radius jet with substructure. The observed data are found to be consistent with the expected Standard Model backgrounds. Model-independent upper limits are placed on the visible cross sections for events with a Higgs boson decaying into b (b) over bar and large missing transverse momentum with thresholds ranging from 150 to 400 GeV. Results are interpreted using a simplified model with a Z' gauge boson decaying into different Higgs bosons predicted in a two-Higgs-doublet model, of which the heavy pseudoscalar Higgs decays into a pair of dark matter particles. Exclusion limits are also presented for the mass scales of various effective field theory operators that describe the interaction between dark matter particles and the Higgs boson.
|
|
| 5. |
- Abulaiti, Yiming, et al.
(författare)
-
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at root s=13 TeV using the ATLAS detector
- 2016
-
Ingår i: Physical Review D. - 2470-0010 .- 1550-7998 .- 1550-2368. ; 94:3
-
Tidskriftsartikel (refereegranskat)abstract
- Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 3.2 fb(-1) at root s = 13 TeV collected in 2015 with the ATLAS detector at the Large Hadron Collider. Events are required to have at least one jet with a transverse momentum above 250 GeV and no leptons. Several signal regions are considered with increasing missing-transverse-momentum requirements between E-T(miss) > 250 GeV and E-T(miss) > 700 GeV. Good agreement is observed between the number of events in data and Standard Model predictions. The results are translated into exclusion limits in models with large extra spatial dimensions, pair production of weakly interacting dark-matter candidates, and the production of supersymmetric particles in several compressed scenarios.
|
|
| 6. |
- Abulaiti, Yiming, et al.
(författare)
-
Search for the standard model Higgs boson produced in association with a vector boson and decaying into a tau pair in pp collisions at root s=8 TeV with the ATLAS detector
- 2016
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 1550-7998 .- 1550-2368. ; 93:9
-
Tidskriftsartikel (refereegranskat)abstract
- A search for the standard model Higgs boson produced in association with a vector boson with the decay H -> tau tau is presented. The data correspond to 20.3 fb(-1) of integrated luminosity from proton-proton collisions at root s = 8 TeV recorded by the ATLAS experiment at the LHC during 2012. The data agree with the background expectation, and 95% confidence-level upper limits are placed on the cross section of this process. The observed (expected) limit, expressed in terms of the signal strength mu= sigma/sigma(SM) for m(H) = 125 GeV, is mu < 5.6 (3.7). The measured value of the signal strength is mu = 2.3 +/- 1.6.
|
|
| 7. |
- Abulaiti, Yiming, et al.
(författare)
-
Study of ordered hadron chains with the ATLAS detector
- 2017
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 96
-
Tidskriftsartikel (refereegranskat)abstract
- The analysis of the momentum difference between charged hadrons in high-energy proton-proton collisions is performed in order to study coherent particle production. The observed correlation pattern agrees with a model of a helical QCD string fragmenting into a chain of ground-state hadrons. A threshold momentum difference in the production of adjacent pairs of charged hadrons is observed, in agreement with model predictions. The presence of low-mass hadron chains also explains the emergence of charge-combination-dependent two-particle correlations commonly attributed to Bose-Einstein interference. The data sample consists of 190 mu b(-1) of minimum-bias events collected with proton-proton collisions at a center-of-mass energy root s = 7 TeV in the early low-luminosity data taking with the ATLAS detector at the LHC.
|
|
| 8. |
- Aaboud, M, et al.
(författare)
-
Measurement of the t t production cross section in the τ+jets final state in pp collisions at s =8 TeV using the ATLAS detector
- 2017
-
Ingår i: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-2368. ; 95:7
-
Tidskriftsartikel (refereegranskat)abstract
- A measurement of the inclusive pp→tt+X production cross section in the τ+jets final state using only the hadronic decays of the τ lepton is presented. The measurement is performed using 20.2 fb-1 of proton-proton collision data recorded at a center-of-mass energy of s=8 TeV with the ATLAS detector at the Large Hadron Collider. The cross section is measured via a counting experiment by imposing a set of selection criteria on the identification and kinematic variables of the reconstructed particles and jets, and on event kinematic variables and characteristics. The production cross section is measured to be σtt=239±29 pb, which is in agreement with the measurements in other final states and the theoretical predictions at this center-of-mass energy. © 2017 CERN.
|
|
| 9. |
- Aaboud, M, et al.
(författare)
-
Measurement of W±W± vector-boson scattering and limits on anomalous quartic gauge couplings with the ATLAS detector MEASUREMENT of W±W± VECTOR-BOSON M. AABOUD et al.
- 2017
-
Ingår i: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-2368. ; 96:1
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the extended results of measurements of W±W±jj production and limits on anomalous quartic gauge couplings using 20.3 fb-1 of proton-proton collision data at s=8 TeV recorded by the ATLAS detector at the Large Hadron Collider. Events with two leptons (e or μ) with the same electric charge and at least two jets are analyzed. Production cross sections are determined in two fiducial regions, with different sensitivities to the electroweak and strong production mechanisms. An additional fiducial region, particularly sensitive to anomalous quartic gauge coupling parameters α4 and α5, is introduced, which allows more stringent limits on these parameters compared to the previous ATLAS measurement. © 2017 CERN.
|
|
| 10. |
- Aaboud, M, et al.
(författare)
-
Search for pair production of Higgs bosons in the b b b b final state using proton-proton collisions at s =13 TeV with the ATLAS detector SEARCH for PAIR PRODUCTION of HIGGS BOSONS in ⋯ M. AABOUD et al.
- 2016
-
Ingår i: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-2368. ; 94:5
-
Tidskriftsartikel (refereegranskat)abstract
- A search for Higgs-boson pair production in the bbbb final state is carried out with 3.2 fb-1 of proton-proton collision data collected at s=13 TeV with the ATLAS detector. The data are consistent with the estimated background and are used to set upper limits on the production cross section of Higgs-boson pairs times branching ratio to bbbb for both nonresonant and resonant production. In the case of resonant production of Kaluza-Klein gravitons within the Randall-Sundrum model, upper limits in the 24 to 91 fb range are obtained for masses between 600 and 3000 GeV, at the 95% confidence level. The production cross section times branching ratio for nonresonant Higgs-boson pairs is also constrained to be less than 1.22 pb, at the 95% confidence level. © 2016 CERN.
|
|
