| 1. |
|
|
| 2. |
-
- 2019
-
Tidskriftsartikel (refereegranskat)
|
|
| 3. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
|
|
| 4. |
- Klionsky, Daniel J., et al.
(författare)
-
Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
-
Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
-
Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
|
|
| 5. |
- Kanoni, Stavroula, et al.
(författare)
-
Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis.
- 2022
-
Ingår i: Genome biology. - : Springer Science and Business Media LLC. - 1474-760X .- 1465-6906 .- 1474-7596. ; 23:1
-
Tidskriftsartikel (refereegranskat)abstract
- Genetic variants within nearly 1000 loci are known to contribute to modulation of blood lipid levels. However, the biological pathways underlying these associations are frequently unknown, limiting understanding of these findings and hindering downstream translational efforts such as drug target discovery.To expand our understanding of the underlying biological pathways and mechanisms controlling blood lipid levels, we leverage a large multi-ancestry meta-analysis (N=1,654,960) of blood lipids to prioritize putative causal genes for 2286 lipid associations using six gene prediction approaches. Using phenome-wide association (PheWAS) scans, we identify relationships of genetically predicted lipid levels to other diseases and conditions. We confirm known pleiotropic associations with cardiovascular phenotypes and determine novel associations, notably with cholelithiasis risk. We perform sex-stratified GWAS meta-analysis of lipid levels and show that 3-5% of autosomal lipid-associated loci demonstrate sex-biased effects. Finally, we report 21 novel lipid loci identified on the X chromosome. Many of the sex-biased autosomal and X chromosome lipid loci show pleiotropic associations with sex hormones, emphasizing the role of hormone regulation in lipid metabolism.Taken together, our findings provide insights into the biological mechanisms through which associated variants lead to altered lipid levels and potentially cardiovascular disease risk.
|
|
| 6. |
- Abbafati, Cristiana, et al.
(författare)
-
- 2020
-
Tidskriftsartikel (refereegranskat)
|
|
| 7. |
- Weinstein, John N., et al.
(författare)
-
The cancer genome atlas pan-cancer analysis project
- 2013
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:10, s. 1113-1120
-
Forskningsöversikt (refereegranskat)abstract
- The Cancer Genome Atlas (TCGA) Research Network has profiled and analyzed large numbers of human tumors to discover molecular aberrations at the DNA, RNA, protein and epigenetic levels. The resulting rich data provide a major opportunity to develop an integrated picture of commonalities, differences and emergent themes across tumor lineages. The Pan-Cancer initiative compares the first 12 tumor types profiled by TCGA. Analysis of the molecular aberrations and their functional roles across tumor types will teach us how to extend therapies effective in one cancer type to others with a similar genomic profile. © 2013 Nature America, Inc. All rights reserved.
|
|
| 8. |
- Akiyama, Kazunori, et al.
(författare)
-
The persistent shadow of the supermassive black hole of M 87: I. Observations, calibration, imaging, and analysis*
- 2024
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 681
-
Tidskriftsartikel (refereegranskat)abstract
- In April 2019, the Event Horizon Telescope (EHT) Collaboration reported the first-ever event-horizon-scale images of a black hole, resolving the central compact radio source in the giant elliptical galaxy M 87. These images reveal a ring with a southerly brightness distribution and a diameter of ∼42 μas, consistent with the predicted size and shape of a shadow produced by the gravitationally lensed emission around a supermassive black hole. These results were obtained as part of the April 2017 EHT observation campaign, using a global very long baseline interferometric radio array operating at a wavelength of 1.3 mm. Here, we present results based on the second EHT observing campaign, taking place in April 2018 with an improved array, wider frequency coverage, and increased bandwidth. In particular, the additional baselines provided by the Greenland telescope improved the coverage of the array. Multiyear EHT observations provide independent snapshots of the horizon-scale emission, allowing us to confirm the persistence, size, and shape of the black hole shadow, and constrain the intrinsic structural variability of the accretion flow. We have confirmed the presence of an asymmetric ring structure, brighter in the southwest, with a median diameter of 43.3-3.1+1.5 μas. The diameter of the 2018 ring is remarkably consistent with the diameter obtained from the previous 2017 observations. On the other hand, the position angle of the brightness asymmetry in 2018 is shifted by about 30 relative to 2017. The perennial persistence of the ring and its diameter robustly support the interpretation that the ring is formed by lensed emission surrounding a Kerr black hole with a mass ∼6.5× 109M. The significant change in the ring brightness asymmetry implies a spin axis that is more consistent with the position angle of the large-scale jet.
|
|
| 9. |
- Flannick, Jason, et al.
(författare)
-
Data Descriptor : Sequence data and association statistics from 12,940 type 2 diabetes cases and controls
- 2017
-
Ingår i: Scientific Data. - : Springer Science and Business Media LLC. - 2052-4463. ; 4
-
Tidskriftsartikel (refereegranskat)abstract
- To investigate the genetic basis of type 2 diabetes (T2D) to high resolution, the GoT2D and T2D-GENES consortia catalogued variation from whole-genome sequencing of 2,657 European individuals and exome sequencing of 12,940 individuals of multiple ancestries. Over 27M SNPs, indels, and structural variants were identified, including 99% of low-frequency (minor allele frequency [MAF] 0.1-5%) non-coding variants in the whole-genome sequenced individuals and 99.7% of low-frequency coding variants in the whole-exome sequenced individuals. Each variant was tested for association with T2D in the sequenced individuals, and, to increase power, most were tested in larger numbers of individuals (> 80% of low-frequency coding variants in similar to ~82 K Europeans via the exome chip, and similar to ~90% of low-frequency non-coding variants in similar to ~44 K Europeans via genotype imputation). The variants, genotypes, and association statistics from these analyses provide the largest reference to date of human genetic information relevant to T2D, for use in activities such as T2D-focused genotype imputation, functional characterization of variants or genes, and other novel analyses to detect associations between sequence variation and T2D.
|
|
| 10. |
- Fuchsberger, Christian, et al.
(författare)
-
The genetic architecture of type 2 diabetes
- 2016
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 536:7614, s. 41-47
-
Tidskriftsartikel (refereegranskat)abstract
- The genetic architecture of common traits, including the number, frequency, and effect sizes of inherited variants that contribute to individual risk, has been long debated. Genome-wide association studies have identified scores of common variants associated with type 2 diabetes, but in aggregate, these explain only a fraction of the heritability of this disease. Here, to test the hypothesis that lower-frequency variants explain much of the remainder, the GoT2D and T2D-GENES consortia performed whole-genome sequencing in 2,657 European individuals with and without diabetes, and exome sequencing in 12,940 individuals from five ancestry groups. To increase statistical power, we expanded the sample size via genotyping and imputation in a further 111,548 subjects. Variants associated with type 2 diabetes after sequencing were overwhelmingly common and most fell within regions previously identified by genome-wide association studies. Comprehensive enumeration of sequence variation is necessary to identify functional alleles that provide important clues to disease pathophysiology, but large-scale sequencing does not support the idea that lower-frequency variants have a major role in predisposition to type 2 diabetes.
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
- Ablikim, M., et al.
(författare)
-
Amplitude analysis of the pi(0)pi(0) system produced in radiative J/psi decays
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:5
-
Tidskriftsartikel (refereegranskat)abstract
- An amplitude analysis of the pi(0)pi(0) system produced in radiative J/psi decays is presented. In particular, a piecewise function that describes the dynamics of the pi(0)pi(0) system is determined as a function of M pi(0)pi(0) from an analysis of the (1.311 +/- 0.011) x 10(9) J/psi decays collected by the BESIII detector. The goal of this analysis is to provide a description of the scalar and tensor components of the pi(0)pi(0) system while making minimal assumptions about the properties or number of poles in the amplitude. Such a model-independent description allows one to integrate these results with other related results from complementary reactions in the development of phenomenological models, which can then be used to directly fit experimental data to obtain parameters of interest. The branching fraction of J/psi -> pi(0)pi(0) is determined to be (1.15 +/- 0.05) x 10(-3), where the uncertainty is systematic only and the statistical uncertainty is negligible.
|
|
| 14. |
- Ablikim, M., et al.
(författare)
-
An improved limit for Gamma(ee) of X(3872) and Gamma(ee) measurement of psi(3686)
- 2015
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 749, s. 414-420
-
Tidskriftsartikel (refereegranskat)abstract
- Using the data sets taken at center-of-mass energies above 4 GeV by the BESIII detector at the BEPCII storage ring, we search for the reaction e(+)e(-) -> gamma(ISR) X(3872) -> gamma(ISR)pi(+)pi(-) J/psi via the Initial State Radiation technique. The production of a resonance with quantum numbers J(PC) = 1(++) such as the X(3872) via single photon e(+)e(-) annihilation is forbidden, but is allowed by a next-to-leading order box diagram. We do not observe a significant signal of X(3872), and therefore give an upper limit for the electronic width times the branching fraction Gamma B-X(3872)(ee)(X(3872) -> pi(+)pi(-) J/psi) < 0.13 eVat the 90% confidence level. This measurement improves upon existing limits by a factor of 46. Using the same final state, we also measure the electronic width of the psi(3686) to be Gamma(psi)(ee)(3686) ee = 2213 +/- 18(stat) +/- 99(sys) eV.
|
|
| 15. |
- Ablikim, M., et al.
(författare)
-
Dark photon search in the mass range between 1.5 and 3.4 GeV/c
- 2017
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 774, s. 252-257
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data set of 2.93 fb taken at a center-of-mass energy root s = 3.773 GeV with the BESIII detector at the BEPCII collider, we perform a search for an extra U(1) gauge boson, also denoted as a dark photon. We examine the initial state radiation reactions e(+)e(-) -> e(+)e(-) gamma(ISR) and e(+)e(-) -> mu(+)mu(-) gamma(ISR) for this search, where the dark photon would appear as an enhancement in the invariant mass distribution of the leptonic pairs. We observe no obvious enhancement in the mass range between 1.5 and 3.4 GeV/c(2) and set a 90% confidence level upper limit on the mixing strength of the dark photon and the Standard Model photon. We obtain a competitive limit in the tested mass range.
|
|
| 16. |
- Ablikim, M., et al.
(författare)
-
Evidence for e(+)e(-)->gamma chi c1,2 at center-of-mass energies from 4.009 to 4.360 GeV
- 2015
-
Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 39:4
-
Tidskriftsartikel (refereegranskat)abstract
- Using data samples collected at center-of-mass energies of root s=4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process e(+)e(-)->gamma chi(cJ) (J=0, 1, 2) and find evidence for e(+)e(-)->gamma chi(c1) and e(+)e(-)->gamma chi(c2) with statistical significances of 3.0 sigma and 3.4 sigma, respectively. The Born cross sections sigma(B)(e(+)e(-)->gamma chi(cJ)), as well as their upper limits at the 90% confidence level (C.L.) are determined at each center-of-mass energy.
|
|
| 17. |
- Ablikim, M., et al.
(författare)
-
Measurement of B(psi(3770) -> gamma chi(c1)) and search for psi(3770) -> gamma chi(c2)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:9
-
Tidskriftsartikel (refereegranskat)abstract
- We report a measurement of the branching fraction for psi(3770) -> gamma chi(c1) and search for the transition psi(3770) -> gamma chi(c2) based on 2.92 fb(-1) of e(+)e(-) data accumulated at root s = 3.773 GeV with the BESIII detector at the BEPCII collider. We measure B(psi(3770) -> gamma chi(c1)) = (2.48 +/- 0.15 +/- 0.23) x 10(-3), which is the most precise measurement to date. The upper limit on the branching fraction of psi(3770) -> gamma chi(c2) at a 90% confidence level is B(psi(3770) -> gamma chi(c2)) < 0.64 x 10(-3). The corresponding partial widths are Gamma(psi(3770) -> gamma chi(c1)) = (67.5 +/- 4.1 +/- 6.7)keV and Gamma(psi(3770) -> gamma chi(c2)) < 17.4 keV.
|
|
| 18. |
- Ablikim, M., et al.
(författare)
-
Measurement of the branching fraction for psi(3686) -> omega K+K-
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:11, s. 112006-
-
Tidskriftsartikel (refereegranskat)abstract
- With 1.06 x 10(8) psi(3686) events collected with the BESIII detector, the branching fraction of psi(3686) -> omega K+K- is measured to be (1.54 +/- 0.04 +/- 0.11) x 10(-4). This is the most precise result to date, due to the largest psi(3686) sample, improved signal reconstruction efficiency, good simulation of the detector performance, and a more accurate knowledge of the continuum contribution. Using the branching fraction of J/psi -> omega K+K-, the ratio B(psi(3868) -> K+K-)/B(J/psi -> K+K-) is determined to be (18.4 +/- 3.7)%. This constitutes a significantly improved test of the 12% rule, with the uncertainty now dominated by the J/psi branching fraction.
|
|
| 19. |
- Ablikim, M., et al.
(författare)
-
Measurement of the branching fractions of D-s(+) -> eta ' X and D-s(+) -> eta 'rho(+) in e(+)e(-) -> Ds+Ds-
- 2015
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 750, s. 466-474
-
Tidskriftsartikel (refereegranskat)abstract
- We study D-s(+) decays to final states involving the eta' with a 482 pb(-1) data sample collected at root s = 4.009 GeV with the BESIII detector at the BEPCII collider. We measure the branching fractions B(D-s(+) -> eta'X) = (8.8 +/- 1.8 +/- 0.5)% and B(D-s(+) > eta'rho(+)) = (5.8 +/- 1.4 +/- 0.4)% where the first uncertainty is statistical and the second is systematic. In addition, we estimate an upper limit on the non-resonant branching ratio B(D-s(+) -> eta'pi(+)pi(0)) < 5.1% at the 90% confidence level. Our results are consistent with CLEO's recent measurements and help to resolve the disagreement between the theoretical prediction and CLEO's previous measurement of B(D-s(+) -> eta'rho(+)).
|
|
| 20. |
|
|
| 21. |
- Ablikim, M., et al.
(författare)
-
Measurement of the leptonic decay width of J/psi using initial state radiation
- 2016
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 761, s. 98-103
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data set of 2.93 fb(-1) taken at a center-of-mass energy of root s = 3.773 GeV with the BESIII detector at the BEPCII collider, we measure the process e(+) e(-) -> J/psi gamma -> mu(+)mu(-)gamma and determine the product of the branching fraction and the electronic width B-mu mu . Gamma(ee) = (333.4 +/- 2.5(stat) +/- 4.4(sys)) eV. Using the earlier-published BESIII result for B-mu mu = (5.973 +/- 0.007(stat) +/- 0.037(sys))%, we derive the J/psi electronic width Gamma(ee) = (5.58 +/- 0.05(stat) +/- 0.08(sys)) keV. (C) 2016 The Author(s). Published by Elsevier B.V.
|
|
| 22. |
- Ablikim, M., et al.
(författare)
-
Measurement of the matrix elements for the decays eta -> pi(+)pi(-)pi(0) and eta/eta ' -> pi(0)pi(0)pi(0)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:1
-
Tidskriftsartikel (refereegranskat)abstract
- Based on a sample of 1.31 x 10(9) J/psi events collected with the BESIII detector at the BEPCII collider, Dalitz plot analyses of selected 79,625 eta -> pi(+)pi(-)pi(0) events, 33,908 eta -> pi(0)pi(0)pi(0) events, and 1,888 eta' -> pi(0)pi(0)pi(0) events are performed. The measured matrix elements of eta -> pi(+)pi(-)pi(0) are in reasonable agreement with previous measurements. The Dalitz plot slope parameters of eta -> pi(0)pi(0)pi(0) and eta' -> pi(0)pi(0)pi(0) are determined to be -0.055 +/- 0.014 +/- 0.004 and -0.640 +/- 0.046 +/- 0.047, respectively, where the first uncertainties are statistical and the second systematic. Both values are consistent with previous measurements, while the precision of the latter one is improved by a factor of 3. Final state interactions are found to have an important role in those decays.
|
|
| 23. |
- Ablikim, M., et al.
(författare)
-
Measurement of the proton form factor by studying e(+)e(-) -> p(p)over-tilde
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:11
-
Tidskriftsartikel (refereegranskat)abstract
- Using data samples collected with the BESIII detector at the BEPCII collider, we measure the Born cross section of e(+)e(-) -> p (p) over tilde at 12 center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective electromagnetic form factor of the proton is deduced under the assumption that the electric and magnetic form factors are equal (vertical bar G(E)vertical bar = vertical bar G(M)vertical bar). In addition, the ratio of electric to magnetic form factors, vertical bar G(E)/G(M)vertical bar, and vertical bar G(M)vertical bar are extracted by fitting the polar angle distribution of the proton for the data samples with larger statistics, namely at root s = 2232.4 and 2400.0 MeV and a combined sample at root s = 3050.0, 3060.0 and 3080.0 MeV, respectively. The measured cross sections are in agreement with recent results from BABAR, improving the overall uncertainty by about 30%. The vertical bar G(E)/G(M)vertical bar ratios are close to unity and consistent with BABAR results in the same q(2) region, which indicates the data are consistent with the assumption that vertical bar G(E)vertical bar = vertical bar G(M)vertical bar within uncertainties.
|
|
| 24. |
- Ablikim, M., et al.
(författare)
-
Measurement of y(CP) in D-0-(D)over-bar(0) oscillation using quantum correlations in e(+)e(-) -> D-0(D)over-bar(0) at root s=3.773 GeV
- 2015
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 744, s. 339-346
-
Tidskriftsartikel (refereegranskat)abstract
- We report a measurement of the parameter y(CP) in D-0-(D) over bar (0) oscillations performed by taking advantage of quantum coherence between pairs of D-0(D) over bar (0) mesons produced in e(+)e(-) annihilations near threshold. In this work, doubly-tagged D-0(D) over bar (0) events, where one D decays to a CP eigenstate and the other D decays in a semileptonic mode, are reconstructed using a data sample of 2.92 fb(-1) collected with the BESIII detector at the center-of-mass energy of root s = 3.773 GeV. We obtain y(CP) = (-2.0 +/- 1.3 +/- 0.7)%, where the first uncertainty is statistical and the second is systematic. This result is compatible with the current world average.
|
|
| 25. |
- Ablikim, M., et al.
(författare)
-
Measurements of psi(3686) -> K-Lambda(Xi)over-bar(+) + c.c. and psi(3686) -> gamma K-Lambda(Xi)over-bar(+) + c.c.
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:9
-
Tidskriftsartikel (refereegranskat)abstract
- Using a sample of 1.06 x 10(8) psi(3686) events produced in e(+)e(-) collisions at root s = 3.686 GeV and collected with the BESIII detector at the BEPCII collider, we present studies of the decays psi(3686) -> K-Lambda(Xi) over bar (+) + c.c. and psi(3686) -> gamma K-Lambda(Xi) over bar (+) + c.c. We observe two hyperons, Xi(1690)(-) and Xi(1820)(-), in the K-Lambda invariant mass distribution in the decay psi(3686) -> K-Lambda(Xi) over bar (+) + c.c. with significances of 4.9 sigma and 6.2 sigma, respectively. The branching fractions of psi(3686) -> K-Lambda(Xi) over bar (+) + c.c., psi(3686) -> K-Sigma(0)(Xi) over bar (+) + c.c, psi(3686) -> gamma chi cJ -> gamma K-Lambda(Xi) over bar (+) + c.c (J = 0, 1, 2), and psi(3686) -> Xi(1690/1820)(-)(Xi) over bar (+) + c.c with sub-sequent decay Xi(1690/1820)(-) -> K-Lambda are measured for the first time.
|
|
| 26. |
- Ablikim, M., et al.
(författare)
-
Observation and Spin-Parity Determination of the X(1835) in J/psi -> gamma(KSKS0)-K-0 eta
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:9
-
Tidskriftsartikel (refereegranskat)abstract
- We report an observation of the process J/psi -> gamma X(1835) -> gamma(KSKS0)-K-0 eta at low (KSKS0)-K-0 mass with a statistical significance larger than 12.9s using a data sample of 1.31 x 109 J/psi events collected with the BESIII detector. In this region of phase space the (KSKS0)-K-0 system is dominantly produced through the f (0)(980). By performing a partial wave analysis, we determine the spin parity of the Xd1835_ to be J(PC) = 0(-+). The mass and width of the observed X(1835) are 1844 +/- 9(stat)(-25)(+16)(syst) MeV/c(2) and 192(-17)(+20)(sta)(-43)(+62)(syst) MeV, respectively, which are consistent with the results obtained by BESIII in the channel J/psi -> gamma pi(+)pi(-)eta'.
|
|
| 27. |
- Ablikim, M., et al.
(författare)
-
Observation of a Neutral Charmoniumlike State Z(c)(4025)(0) in e(+)e(-) -> (D*(D)over-bar*)(0)pi(0)
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:18
-
Tidskriftsartikel (refereegranskat)abstract
- We report a study of the process e(+)e(-) -> (D*(D) over bar*)(0)pi(0) using e(+)e(-) collision data samples with integrated luminosities of 1092 pb(-1) at root s = 4.23 GeV and 826 pb(-1) at root s = 4.26 GeV collected with the BESIII detector at the BEPCII storage ring. We observe a new neutral structure near the (D*(D) over bar*)(0) mass threshold in the pi(0) recoil mass spectrum, which we denote as Z(c)(4025)(0). Assuming a Breit-Wigner line shape, its pole mass and pole width are determined to be (4025.5(-4.7)(+2.0) +/- 3.1) MeV/c(2) and (23.0 +/- 6.0 +/- 1.0) MeV, respectively. The Born cross sections of e(+)e(-) -> Z(c)(4025)(0)pi(0) -> (D*(D) over bar*)(0)pi(0) are measured to be (61.6 +/- 8.2 +/- 9.0) pb at root s = 4.23 GeV and (43.4 +/- 8.0 +/- 5.4) pb at root s = 4.26 GeV. The first uncertainties are statistical and the second are systematic.
|
|
| 28. |
- Ablikim, M., et al.
(författare)
-
Observation of e(+)e(-) -> pi(0)pi(0)h(c) and a Neutral Charmoniumlike Structure Z(c)(4020)(0)
- 2014
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 113:21, s. 212002-
-
Tidskriftsartikel (refereegranskat)abstract
- Using data collected with the BESIII detector operating at the Beijing Electron Positron Collider at center-of-mass energies of root s = 4.23, 4.26, and 4.36 GeV, we observe e(+)e(-) -> pi(0)pi(0)h(c) for the first time. The Born cross sections are measured and found to be about half of those of e(+)e(-) -> pi(+)pi(-)h(c) within less than 2 sigma. In the pi(0)h(c) mass spectrum, a structure at 4.02 GeV/c(2) is found. It is most likely to be the neutral isospin partner of the Z(c)(4020)(+/-) observed in the process of e(+)e(-) -> pi(+)pi(-)h(c) being found. A fit to the pi(0)h(c) invariant mass spectrum, with the width of the Z(c)(4020)(0) fixed to that of its charged isospin partner and possible interferences with non-Z(c)(4020)(0) amplitudes neglected, gives a mass of (4023.9 +/- 2.2 +/- 3.8) MeV/c(2) for the Z(c)(4020)(0), where the first error is statistical and the second systematic.
|
|
| 29. |
- Ablikim, M., et al.
(författare)
-
Observation of J/psi -> p(p)over-bara(0)(980) at BESIII
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:5, s. 052009-
-
Tidskriftsartikel (refereegranskat)abstract
- Using 2.25 x 10(8) J/psi events collected with the BESIII detector at the BEPCII storage rings, we observe for the first time the process J/psi -> p (p) over bara(0)(980) -> pi(0)eta with a significance of 6.5 sigma (3.2 sigma including systematic uncertainties). The product branching fraction of J/psi -> p (p) over bara(0)(980) -> p (p) over bara(0)pi(0)eta is measured to be (6.8 +/- 1.2 +/- 1.3) x 10(-5), where the first error is statistical and the second is systematic. This measurement provides information on the a(0) production near threshold coupling to p (p) over bar and improves the understanding of the dynamics of J/psi decays to four-body processes.
|
|
| 30. |
- Ablikim, M., et al.
(författare)
-
Observation of the Dalitz decay eta ' -> gamma e(+)e(-)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:1
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first observation of the Dalitz decay eta' -> gamma e(+)e(-), based on a data sample of 1.31 billion J/psi events collected with the BESIII detector. The eta' mesons are produced via the J/psi -> gamma eta' decay process. The ratio (eta' -> gamma e(+)e(-))/Gamma (eta' -> gamma gamma) is measured to be (2.13 +/- 0.09(stat) +/- 0.07(sys)) x 10(-2). This corresponds to a branching fraction B(eta' -> gamma e(+)e(-)) = (4.69 +/- 0.20(stat) +/- 0.23(sys)) x 10(-4). The transition form factor is extracted and different expressions are compared to the measured dependence on the e(+)e(-) invariant mass. The results are consistent with the prediction of the vector meson dominance model.
|
|
| 31. |
- Ablikim, M., et al.
(författare)
-
Observation of the electromagnetic doubly OZI-suppressed decay J/psi -> phi pi(0)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:11
-
Tidskriftsartikel (refereegranskat)abstract
- Using a sample of 1.31 billion J/psi events accumulated with the BESIII detector at the BEPCII collider, we report the observation of the decay J/psi -> phi pi(0), which is the first evidence for a doubly Okubo-Zweig-Iizuka suppressed electromagnetic J/psi decay. A clear structure is observed in the K+K- mass spectrum around 1.02 GeV/c(2), which can be attributed to interference between J/psi -> phi pi(0) and J/psi -> K+K- pi(0) decays. Due to this interference, two possible solutions are found. The corresponding measured values of the branching fraction of J/psi -> phi pi(0) are [2.94 +/- 0.16(stat) +/- 0.16(syst)] x 10(-6) and [1.24 +/- 0.33(stat) +/- 0.30(syst)] x 10(-7).
|
|
| 32. |
- Ablikim, M., et al.
(författare)
-
Observation of the isospin-violating decay J/psi -> phi pi(0)f(0) (980)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:1
-
Tidskriftsartikel (refereegranskat)abstract
- Using a sample of 1.31 x 10(9) J/psi events collected with the BESIII detector at the BEPCII collider, the decays J/psi -> phi pi(+)pi(-)pi(0) and J/psi -> phi pi(0)pi(0)pi(0) are investigated. The isospin- violating decay J/psi -> phi pi(0)f(0)(980) with f(0)(980)-> pi pi is observed for the first time. The width of the f(0)(980) obtained from the dipion mass spectrum is found to be much smaller than the world average value. In the pi(0)f(0)(980) mass spectrum, there is evidence of f(1)(1285) production. By studying the decay J/psi ->eta', the branching fractions of eta' -> pi(+)pi(-)pi(0) and eta' -> pi(0)pi(0)pi(0), as well as their ratio, are also measured.
|
|
| 33. |
- Ablikim, M., et al.
(författare)
-
Observation of the Psi(1(3)D(2)) State in e(+)e(-) -> pi(+)pi(-)gamma chi(c1) at BESIII
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:1
-
Tidskriftsartikel (refereegranskat)abstract
- We report the observation of the X(3823) state in the process e(+)e(-) -> pi(+)pi(-) X(3823) pi(+)pi(-)gamma chi(c1) with a statistical significance of 6.2 sigma, in data samples at center-of-mass energies root s = 4.230, 4.260, 4.360, 4.420, and 4.600 GeV collected with the BESIII detector at the BEPCII electron positron collider. The measured mass of the X(3823) state is (3821.7 +/- 1.3 +/- 0.7) MeV/c(2), where the first error is statistical and the second systematic, and the width is less than 16 MeV at the 90% confidence level. The products of the Born cross sections for e(+)e(-) -> pi(+)pi(-) X(3823) and the branching ratio B [X(3823) -> gamma X-c1c2] are also measured. These measurements are in good agreement with the assignment of the X(3823) state as the Psi(1(3)D(2)) charmonium state.
|
|
| 34. |
- Ablikim, M., et al.
(författare)
-
Observation of Z(c)(3900)(0) in e(+)e(-) -> pi(0)pi(0) J/Psi
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:11
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data sample collected with the BESIII detector operating at the BEPCII storage ring, we observe a new neutral state Z(c)(3900)(0) with a significance of 10.4 sigma. The mass and width are measured to be 3894.8 +/- 2.3 +/- 3.2 MeV/c(2) and 29.6 +/- 8.2 +/- 8.2 MeV, respectively, where the first error is statistical and the second systematic. The Born cross section for e(+)e(-) -> pi(0)pi(0) J/Psi and the fraction of it attributable to pi(0)Z(c)(3900)(0) -> pi(0)pi(0) J/Psi in the range E-c.m. = 4.19-4.42 GeV are also determined. We interpret this state as the neutral partner of the four-quark candidate Z(c)(3900)(+/-).
|
|
| 35. |
- Ablikim, M., et al.
(författare)
-
Precision measurement of the D*(0) decay branching fractions
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368 .- 2470-0010. ; 91:3
-
Tidskriftsartikel (refereegranskat)abstract
- Using 482 pb(-1) of data taken at root s = 4.009 GeV, we measure the branching fractions of the decays of D*(0) into D-0 pi(0) and D-0 gamma to be B(D*(0) -> D-0 pi(0)) = (65.5 +/- 0.8 +/- 0.5)% and B(D*(0) -> D0 gamma) = (34.5 +/- 0.8 +/- 0.5)%, respectively, by assuming that the D*(0) decays only into these two modes. The ratio of the two branching fractions is B(D*(0) -> D-0 pi(0))/B(D*(0) -> D-0 gamma) = 1.90 +/- 0.07 +/- 0.05, which is independent of the assumption made above. The first uncertainties are statistical and the second ones systematic. The precision is improved by a factor of 3 compared to the present world average values.
|
|
| 36. |
|
|
| 37. |
- Ablikim, M., et al.
(författare)
-
Search for C-parity violation in J/psi -> gamma gamma and gamma phi
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:9, s. 092002-
-
Tidskriftsartikel (refereegranskat)abstract
- Using 1.06 x 10(8) psi(3686) events recorded in e(+)e(-) collisions at root s = 3.686 GeV with the BESIII at the BEPCII collider, we present searches for C-parity violation in J/psi -> gamma gamma and gamma phi decays via psi(3686) -> J/psi pi(+)pi(-). No significant signals are observed in either channel. Upper limits on the branching fractions are set to be B(J/psi -> gamma gamma) < 2.7 x 10(-7) and B(J/psi -> gamma phi) < 1.4 x 10(-6) at the 90% confidence level. The former is one order of magnitude more stringent than the previous upper limit, and the latter represents the first limit on this decay channel.
|
|
| 38. |
- Ablikim, M., et al.
(författare)
-
Search for D-0 -> gamma gamma and improved measurement of the branching fraction for D-0 -> pi(0)pi(0)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:11
-
Tidskriftsartikel (refereegranskat)abstract
- Using 2.92 fb(-1) of electron-positron annihilation data collected at root s = 3.773 GeV with the BESIII detector, we report the results of a search for the flavor-changing neutral current process D-0 -> gamma gamma using a double-tag technique. We find no signal and set an upper limit at 90% confidence level for the branching fraction of B(D-0 -> gamma gamma < 3.8 x 10(-6). We also investigate D-0-meson decay into two neutral pions, obtaining a branching fraction of B(D-0 -> pi(0)pi(0)) = (8.24 +/- 0.21(stat) +/- 0.30(syst)) x 10(-4), the most precise measurement to date and consistent with the current world average.
|
|
| 39. |
- Ablikim, M., et al.
(författare)
-
Search for the isospin violating decay Y(4260)-> J/psi eta pi(0)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:1
-
Tidskriftsartikel (refereegranskat)abstract
- Using data samples collected at center-of-mass energies of root s = 4.009, 4.226, 4.257, 4.358, 4.416, and 4.599 GeV with the BESIII detector operating at the BEPCII storage ring, we search for the isospin violating decay Y(4260)-> J/psi eta pi(0). No signal is observed, and upper limits on the cross section sigma(e(+)e(-) -> J/psi eta pi(0)) at the 90% confidence level are determined to be 3.6, 1.7, 2.4, 1.4, 0.9, and 1.9 pb, respectively.
|
|
| 40. |
- Ablikim, M., et al.
(författare)
-
Search for the weak decays J/psi -> D-s(()*()-) e(+)nu(e) + c.c.
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:11, s. 112014-
-
Tidskriftsartikel (refereegranskat)abstract
- Using a sample of 2.25 x 10(8) J/psi events collected with the BESIII detector at the BEPCII collider, we search for the J/psi semileptonic weak decay J/psi -> D-s(-) e(+)nu(e) +c.c. with a much higher sensitivity than previous searches. We also perform the first search for J/psi -> D-s(*-) e(+) nu(e) + c.c. No significant excess of a signal above background is observed in either channel. At the 90% confidence level, the upper limits are determined to be B(J/psi -> D-s(-) e(+) nu(e) + c.c.) < 1.3 x 10(-6) and B(J/psi -> D-s*(-) e(+) nu(e) + c.c.) < 1.8 x 10(-6), respectively. Both are consistent with Standard Model predictions.
|
|
| 41. |
- Ablikim, M., et al.
(författare)
-
Search for the Y(4140) via e(+)e(-) -> gamma phi J/psi at root s=4.23, 4.26 and 4.36 GeV
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:3
-
Tidskriftsartikel (refereegranskat)abstract
- Using data samples collected at center-of-mass energies root s = 4.23, 4.26, and 4.36 GeV with the BESIII detector operating at the BEPCII storage ring, we search for the production of the charmoniumlike state Y(4140) through a radiative transition followed by its decay to phi J/psi. No significant signal is observed and upper limits on sigma[e(+)e(-) -> gamma Y(4140)] . B(Y(4140) -> phi J/psi at the 90% confidence level are estimated as 0.35, 0.28, and 0.33 pb at root s = 4.23, 4.26, and 4.36 GeV, respectively.
|
|
| 42. |
- Ablikim, M., et al.
(författare)
-
Search for Z(c)(3900)(+/-) -> omega pi(+/-)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:3
-
Tidskriftsartikel (refereegranskat)abstract
- The decay Z(c)(3900)(+/-) -> omega pi(+/-) is searched for using data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies root s = 4.23 and 4.26 GeV. No significant signal for the Z(c)(3900)(+/-) is found, and upper limits at the 90% confidence level on the Born cross section for the process e(+)e(-) -> Z(c)(3900)(+/-) pi(-/+) -> omega pi(+)pi(-) are determined to be 0.26 and 0.18 pb at root s = 4.23 and 4.26 GeV, respectively.
|
|
| 43. |
- Ablikim, M., et al.
(författare)
-
Searches for isospin-violating transitions chi(c0,2) -> pi(0)eta(c)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:11
-
Tidskriftsartikel (refereegranskat)abstract
- We present the first upper-limit measurement of the branching fractions of the isospin-violating transitions chi(c0,2) -> pi(0)eta(c). The measurements are performed using 106 x 10(6) psi(3686) events accumulated with the BESIII detector at the BEPCII e(+)e(-) collider at a center-of-mass energy corresponding to the psi(3686) mass. We obtained upper limits on the branching fractions at a 90% confidence level of B(chi(c0) -> pi(0)eta(c)) < 1.6 x 10(-3) and B(chi(c2) -> pi(0)eta(c)) < 3.2 x 10(-3).
|
|
| 44. |
- Ablikim, M., et al.
(författare)
-
Study of chi(cJ) decaying into phi K*(892)(K)over-bar
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:11
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data sample of 106 million psi(3686) events collected with the BESIII detector operated at the BEPCII storage ring, we study for the first time the decays chi(cJ) -> phi(KSK +/-)-K-0 pi(-/+) and chi(cJ) -> phi K+K-pi(0) in the E1 radiative transition psi(3686) -> gamma chi(cJ). The decays are dominated by the three-body decay chi(cJ) -> phi K*(892)(K) over bar. We measure branching fractions for this reaction via the neutral and charged K*(892) and find them consistent with each other within the expectation of isospin symmetry. In the K (K) over bar pi invariant mass distribution, a structure near the K*(892)(K) over bar mass threshold is observed, and the corresponding mass and width are measured to be 1412 +/- 4(stat) +/- 8(sys) MeV/c(2) and Gamma = 84 +/- 12(stat) +/- 40(sys) MeV, respectively. The observed state favors an assignment to the h(1)(1380), considering its possible J(PC) and comparing its mass, width and decay mode to those reported in the Particle Data Group.
|
|
| 45. |
- Ablikim, M., et al.
(författare)
-
Study of e(+)e(-) -> omega chi(cJ) at Center of Mass Energies from 4.21 to 4.42 GeV
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 114:9
-
Tidskriftsartikel (refereegranskat)abstract
- Based on data samples collected with the BESIII detector at the BEPCII collider at nine center of mass energies from 4.21 to 4.42 GeV, we search for the production of e(+)e(-) -> omega chi(cJ) (J = 0, 1, 2). The process e(+)e(-) -> omega chi(c0) is observed for the first time, and the Born cross sections at root s = 4.23 and 4.26 GeV are measured to be (55.4 +/- 6.0 +/- 5.9) and (23.7 +/- 5.3 +/- 3.5) pb, respectively, where the first uncertainties are statistical and the second are systematic. The omega chi(c0) signals at the other seven energies and the e(+)e(-) -> omega chi(c1) and omega chi(c2) signals are not significant, and the upper limits on the cross sections are determined. By examining the omega chi(c0) cross section as a function of center of mass energy, we find that it is inconsistent with the line shape of the Y(4260) observed in e(+)e(-) -> pi(+)pi(-) J/psi Assuming the omega chi(c0) signals come from a single resonance, we extract the mass and width of the resonance to be (4230 +/- 8 +/- 6) MeV/c(2) and (38 +/- 12 +/- 2) MeV, respectively, and the statistical significance is more than 9 sigma.
|
|
| 46. |
- Ablikim, M., et al.
(författare)
-
Study of J/psi -> eta phi pi(+)pi(-) at BESIII
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:5
-
Tidskriftsartikel (refereegranskat)abstract
- invariant mass spectrum of phi f(0)(980) with a statistical significance of greater than 10 sigma. The corresponding mass and width are determined to be M = 2200 +/- 6(stat) +/- 5(syst) MeV/c(2) and Gamma = 104 +/- 15(stat) +/- 15(syst) MeV, respectively, and the product branching fraction is measured to be B(J/psi ->eta Y(2175), Y(2175)->phi f(0)(980), f(0)(980)->pi(+)pi(-)) = (1.20 +/- 0.14(stat)+/- 0.37(syst))x10(-4). The results are consistent within errors with those of previous experiments. We also measure the branching fraction of J/psi ->phi f(1)(1285) with f(1)(1285)->eta pi(+)pi(-) and set upper limits on the branching fractions for J/psi ->phi eta(1405)/phi X(1835)/phi X(1870) with eta(1405)/X(1835)/X(1870)->eta pi(+)pi(-) at the 90% confidence level.
|
|
| 47. |
- Adare, A., et al.
(författare)
-
Cross section and transverse single-spin asymmetry of eta mesons in p up arrow plus p collisions at root s=200 GeV at forward rapidity
- 2014
-
Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 90:7
-
Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the cross section and transverse single-spin asymmetry (AN) for. mesons at large pseudorapidity from root s = 200 GeV p up arrow + p collisions. The measured cross section for 0.5 < p(T) < 5.0 GeV/c and 3.0 < vertical bar eta vertical bar < 3.8 is well described by a next-to-leading-order perturbative-quantum-chromodynamics calculation. The asymmetries A(N) have been measured as a function of Feynman-x (x(F)) from 0.2 < vertical bar x(F)vertical bar < 0.7, as well as transverse momentum (p(T)) from 1.0 < p(T) < 4.5 GeV/c. The asymmetry averaged over positive x(F) is < A(N)> = 0.061 +/- 0.014. The results are consistent with prior transverse single-spin measurements of forward eta and pi(0) mesons at various energies in overlapping x(F) ranges. Comparison of different particle species can help to determine the origin of the large observed asymmetries in p up arrow + p collisions.
|
|
| 48. |
- Adare, A., et al.
(författare)
-
Low-mass vector-meson production at forward rapidity in p plus p collisions at root s=200 GeV
- 2014
-
Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 90:5
-
Tidskriftsartikel (refereegranskat)abstract
- The PHENIX experiment at the Relativistic Heavy Ion Collider has measured low-mass vector-meson ,omega, rho, and phi, production through the dimuon decay channel at forward rapidity (1.2 < vertical bar y vertical bar < 2.2) in p + p collisions at root s = 200 GeV. The differential cross sections for these mesons are measured as a function of both p(T) and rapidity. We also report the integrated differential cross sections over 1 < p(T) < 7 GeV/c and 1.2 < vertical bar y vertical bar < 2.2: d sigma/dy(omega + rho rho -> mu mu) = 80 +/- 6(stat) +/- 12(syst)nb and d sigma/dy(phi -> mu mu) = 27 +/- 3(stat) +/- 4(syst)nb. These results are compared with midrapidity measurements and calculations.
|
|
| 49. |
- Adare, A., et al.
(författare)
-
Measurement of K-S(0) and K*(0) in p plus p, d plus Au, and Cu plus Cu collisions at root s(NN)=200 GeV
- 2014
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 90:5
-
Tidskriftsartikel (refereegranskat)abstract
- The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of K-S(0) and K*(0) meson production at midrapidity in p + p, d + Au, and Cu + Cu collisions at root s(NN) = 200 GeV. The K-S(0) and K*(0) mesons are reconstructed via their K-S(0) -> pi(0)(-> gamma gamma) pi(0)(-> gamma gamma) and K*(0) -> K-+/-pi(-/+) decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of K-S(0) and K*(0) mesons in d + Au and Cu + Cu collisions at different centralities. In the d + Au collisions, the nuclear modification factor of K-S(0) and K*(0) mesons is almost constant as a function of transverse momentum and is consistent with unity, showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu + Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p + p yield scaled by the number of binary nucleon-nucleon collisions in the Cu + Cu system. In the p(T) range 2-5 GeV/c, the strange mesons (K-S(0), K*(0)) similarly to the phi meson with hidden strangeness, showan intermediate suppression between the more suppressed light quark mesons (pi(0)) and the nonsuppressed baryons (p, (p) over bar). At higher transverse momentum, p(T) > 5 GeV/c, production of all particles is similarly suppressed by a factor of approximate to 2.
|
|
| 50. |
- Adare, A., et al.
(författare)
-
Measurements of Elliptic and Triangular Flow in High-Multiplicity He-3 + Au Collisions at root s(NN)=200 GeV
- 2015
-
Ingår i: Physical Review Letters. - 1079-7114. ; 115:14
-
Tidskriftsartikel (refereegranskat)abstract
- We present the first measurement of elliptic (v(2)) and triangular (v(3)) flow in high-multiplicity He-3 + Au collisions at root s(NN) = 200 GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in He-3 + Au and in p + p collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the He-3 + Au system. The collective behavior is quantified in terms of elliptic v(2) and triangular v(3) anisotropy coefficients measured with respect to their corresponding event planes. The v(2) values are comparable to those previously measured in d + Au collisions at the same nucleon-nucleon center-of-mass energy. Comparisons with various theoretical predictions are made, including to models where the hot spots created by the impact of the three He-3 nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.
|
|
