| 51. |
- Adare, A., et al.
(författare)
-
Measurement of transverse-single-spin asymmetries for midrapidity and forward-rapidity production of hadrons in polarized p plus p collisions at root s=200 and 62.4 GeV
- 2014
-
Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 90:1
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of transverse-single-spin asymmetries (A(N)) in p + p collisions at root s = 62.4 and 200 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider are presented. At midrapidity, A(N) is measured for neutral pion and eta mesons reconstructed from diphoton decay, and, at forward rapidities, neutral pions are measured using both diphotons and electromagnetic clusters. The neutral-pion measurement of A(N) at midrapidity is consistent with zero with uncertainties a factor of 20 smaller than previous publications, which will lead to improved constraints on the gluon Sivers function. At higher rapidities, where the valence quark distributions are probed, the data exhibit sizable asymmetries. In comparison with previous measurements in this kinematic region, the new data extend the kinematic coverage in root s and p(T), and it is found that the asymmetries depend only weakly on root s. The origin of the forward A(N) is presently not understood quantitatively. The extended reach to higher p(T) probes the transition between transverse momentum dependent effects at low p(T) and multiparton dynamics at high p(T).
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| 52. |
- Adare, A., et al.
(författare)
-
Cross section and double helicity asymmetry for eta mesons and their comparison to pi(0) production in p plus p collisions at root s=200 GeV
- 2011
-
Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 83:3
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of double-helicity asymmetries in inclusive hadron production in polarized p + p collisions are sensitive to helicity-dependent parton distribution functions, in particular, to the gluon helicity distribution, Delta g. This study focuses on the extraction of the double-helicity asymmetry in eta production ((p) over right arrow + (p) over right arrow -> eta + X), the eta cross section, and the eta/pi(0) cross section ratio. The cross section and ratio measurements provide essential input for the extraction of fragmentation functions that are needed to access the helicity-dependent parton distribution functions.
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| 53. |
- Adare, A., et al.
(författare)
-
Identified charged hadron production in p plus p collisions at root s=200 and 62.4 GeV
- 2011
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 83:6
-
Tidskriftsartikel (refereegranskat)abstract
- Transverse momentum distributions and yields for pi(+/-), K-+/-, p, and (p) over bar in p + p collisions at root s = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). These data provide important baseline spectra for comparisons with identified particle spectra in heavy ion collisions at RHIC. We present the inverse slope parameter T-inv, mean transverse momentum < p(T)>, and yield per unit rapidity dN/dy at each energy, and compare them to other measurements at different root s in p + p and p + (p) over bar collisions. We also present the scaling properties such as m(T) scaling and x(T) scaling on the p(T) spectra between different energies. To discuss the mechanism of the particle production in p + p collisions, the measured spectra are compared to next-to-leading-order or next-to-leading-logarithmic perturbative quantum chromodynamics calculations.
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| 54. |
- Adare, A., et al.
(författare)
-
Measurement of Bottom Versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p plus p Collisions at s=200 GeV
- 2009
-
Ingår i: Physical Review Letters. - 1079-7114. ; 103:8
-
Tidskriftsartikel (refereegranskat)abstract
- The momentum distribution of electrons from semileptonic decays of charm and bottom quarks for midrapidity |y|< 0.35 in p+p collisions at s=200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider over the transverse momentum range 2 < p(T)< 7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D -> e(+/-)K(-/+)X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in p(T). A fixed-order-plus-next-to-leading-log perturbative quantum chromodynamics calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is sigma(bb)=3.2(-1.1)(+1.2)(stat)(-1.3)(+1.4)(syst)mu b.
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| 55. |
- Adare, A, et al.
(författare)
-
Measurement of Long-Range Angular Correlation and Quadrupole Anisotropy of Pions and (Anti)Protons in Central d+Au Collisions at sqrt[s_{NN}]=200 GeV.
- 2015
-
Ingår i: Physical Review Letters. - 1079-7114. ; 114:19
-
Tidskriftsartikel (refereegranskat)abstract
- We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d+Au and minimum bias p+p collisions at sqrt[s_{NN}]=200 GeV. The charged hadron is measured at midrapidity |η|<0.35, and the energy is measured at large rapidity (-3.7<η<-3.1, Au-going direction). An enhanced near-side angular correlation across |Δη|>2.75 is observed in d+Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v_{2} for inclusive charged hadrons at midrapidity up to p_{T}=4.5 GeV/c. We also present the measurement of v_{2} for identified π^{±} and (anti)protons in central d+Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p+Pb at sqrt[s_{NN}]=5.02 TeV. The magnitude of the mass ordering in d+Au is found to be smaller than that in p+Pb collisions, which may indicate smaller radial flow in lower energy d+Au collisions.
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| 56. |
- Adare, A., et al.
(författare)
-
Measurement of neutral mesons in p plus p collisions at root s=200 GeV and scaling properties of hadron production
- 2011
-
Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 83:5
-
Tidskriftsartikel (refereegranskat)abstract
- The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the invariant differential cross section for production of K-S(0), omega, eta', and phi mesons in p + p collisions at root s 200 GeV. Measurements of omega and phi production in different decay channels give consistent results. New results for the omega are in agreement with previously published data and extend the measured p(T) coverage. The spectral shapes of all hadron transverse momentum distributions measured by PHENIX are well described by a Tsallis distribution functional form with only two parameters, n and T, determining the high-p(T) and characterizing the low-p(T) regions of the spectra, respectively. The values of these parameters are very similar for all analyzed meson spectra, but with a lower parameter T extracted for protons. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.
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| 57. |
- Adare, A., et al.
(författare)
-
Onset of pi(0) Suppression Studied in Cu plus Cu Collisions at root s(NN)=22.4, 62.4, and 200 GeV
- 2008
-
Ingår i: Physical Review Letters. - 1079-7114. ; 101:16
-
Tidskriftsartikel (refereegranskat)abstract
- Neutral pion transverse momentum (p(T)) spectra at midrapidity (|y| less than or similar to 0.35) were measured in Cu + Cu collisions at root s(NN) = 22.4, 62.4, and 200 GeV. Relative to pi(0) yields in p + p collisions scaled by the number of inelastic nucleon-nucleon collisions (N-coll) the pi(0) yields for p(T) greater than or similar to 2 GeV/c in central Cu + Cu collisions are suppressed at 62.4 and 200 GeV whereas an enhancement is observed at 22.4 GeV. A comparison with a jet-quenching model suggests that final state parton energy loss dominates in central Cu + Cu collisions at 62.4 and 200 GeV, while the enhancement at 22.4 GeV is consistent with nuclear modifications in the initial state alone.
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| 58. |
- Adler, S. S., et al.
(författare)
-
High transverse momentum eta meson production in p+p, d+Au, and Au+Au collisions at root s(NN)=200 GeV
- 2007
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 75:2
-
Forskningsöversikt (refereegranskat)abstract
- Inclusive transverse momentum spectra of eta mesons in the range p(T)approximate to 2-12 GeV/c have been measured at midrapidity (vertical bar eta vertical bar < 0.35) by the PHENIX experiment at RHIC in p+p,d+Au, and Au+Au collisions at root s(NN)=200 GeV. The eta mesons are reconstructed through their eta ->gamma gamma channel for the three colliding systems as well as through the eta ->pi(0)pi(+)pi(-) decay mode in p+p and d+Au collisions. The nuclear modification factor in d+Au collisions, R-dAu(p(T))approximate to 1.0-1.1, suggests at most only modest p(T) broadening ("Cronin enhancement"). In central Au+Au reactions, the eta yields are significantly suppressed, with R-AuAu(p(T))approximate to 0.2. The ratio of eta to pi(0) yields is approximately constant as a function of p(T) for the three colliding systems in agreement with the high-p(T) world average of R-eta/pi(0)approximate to 0.5 in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions for a wide range of center-of-mass energies (root sNN approximate to 3-1800 GeV) as well as, for high scaled momentum x(p), in e(+)e(-) annihilations at root s=91.2 GeV. These results are consistent with a scenario where high-p(T) eta production in nuclear collisions at the Relativistic Heavy Ion Collider is largely unaffected by initial-state effects but where light-quark mesons (pi(0),eta) are equally suppressed due to final-state interactions of the parent partons in the dense medium produced in Au+Au reactions.
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| 59. |
- Namkoong, H, et al.
(författare)
-
DOCK2 is involved in the host genetics and biology of severe COVID-19
- 2022
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 609:7928, s. 754-
-
Tidskriftsartikel (refereegranskat)abstract
- Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge1–5. Here we conducted a genome-wide association study (GWAS) involving 2,393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3,289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target.
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| 60. |
- Aartsen, M. G., et al.
(författare)
-
All-flavour search for neutrinos from dark matter annihilations in the Milky Way with IceCube/DeepCore
- 2016
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 76:10
-
Tidskriftsartikel (refereegranskat)abstract
- We present the first IceCube search for a signal of dark matter annihilations in the Milky Way using all-flavour neutrino-induced particle cascades. The analysis focuses on the DeepCore sub-detector of IceCube, and uses the surrounding IceCube strings as a veto region in order to select starting events in the DeepCore volume. We use 329 live-days of data from IceCube operating in its 86-string configuration during 2011-2012. No neutrino excess is found, the final result being compatible with the background-only hypothesis. From this null result, we derive upper limits on the velocity-averaged self-annihilation cross-section, , for dark matter candidate masses ranging from 30 GeV up to 10 TeV, assuming both a cuspy and a flat-cored dark matter halo profile. For dark matter masses between 200 GeV and 10 TeV, the results improve on all previous IceCube results on , reaching a level of 10 cm s, depending on the annihilation channel assumed, for a cusped NFW profile. The analysis demonstrates that all-flavour searches are competitive with muon channel searches despite the intrinsically worse angular resolution of cascades compared to muon tracks in IceCube.
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