| 1. |
- Adcox, K, et al.
(författare)
-
Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX Collaboration
- 2005
-
Ingår i: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474. ; 757:1-2, s. 184-283
-
Forskningsöversikt (refereegranskat)abstract
- Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (PT), elliptic flow, two-particle correlations, nonstatistical fluctuations, and suppression of particle production at high PT. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.
|
|
| 2. |
|
|
| 3. |
- Adler, SS, et al.
(författare)
-
Common suppression pattern of eta and pi(0) mesons at high transverse momentum in Au plus Au collisions at root SNN=200 GeV
- 2006
-
Ingår i: Physical Review Letters. - 1079-7114. ; 96:20
-
Tidskriftsartikel (refereegranskat)abstract
- Inclusive transverse momentum spectra of eta mesons have been measured within p(T)=2-10 GeV/c at midrapidity by the PHENIX experiment in Au+Au collisions at root s(NN) = 200 GeV. In central Au+Au the eta yields are significantly suppressed compared to peripheral Au+Au, d+Au, and p+p yields scaled by the corresponding number of nucleon-nucleon collisions. The magnitude, centrality, and p(T) dependence of the suppression is common, within errors, for eta and pi(0). The ratio of eta to pi(0) spectra at high p(T) amounts to 0.40 < R-eta/pi(0)< 0.48 for the three systems, in agreement with the world average measured in hadronic and nuclear reactions and, at large scaled momentum, in e(+)e(-) collisions.
|
|
| 4. |
- Adler, SS, et al.
(författare)
-
Deuteron and antideuteron production in Au+Au collisions at root s(NN)=200 GeV
- 2005
-
Ingår i: Physical Review Letters. - 1079-7114. ; 94:12
-
Tidskriftsartikel (refereegranskat)abstract
- The production of deuterons and antideuterons in the transverse momentum range 1.1 < p(T)< 4.3 GeV/c at midrapidity in Au+Au collisions at root s(NN) = 200 GeV has been studied by the PHENIX experiment at RHIC. A coalescence analysis, comparing the deuteron and antideuteron spectra with that of proton and antiproton, has been performed. The coalescence probability is equal for both deuterons and antideuterons and it increases as a function of p(T), which is consistent with an expanding collision zone. Comparing (anti)proton yields, (p) over bar /p = 0.73 +/- 0.01, with (anti)deuteron yields, (d) over bar /d = 0.47 +/- 0.03, we estimate that (n) over bar /n = 0.64 +/- 0.04. The nucleon phase space density is estimated from the coalescence measurement.
|
|
| 5. |
|
|
| 6. |
- Adler, SS, et al.
(författare)
-
Measurement of single electron event anisotropy in Au plus Au collisions at root s(NN)=200 GeV
- 2005
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 72:2
-
Tidskriftsartikel (refereegranskat)abstract
- The transverse momentum dependence of the azimuthal anisotropy parameter v(2), the second harmonic of the azimuthal distribution, for electrons at midrapidity (vertical bar eta vertical bar < 0.35) has been measured with the PHENIX detector in Au+Au collisions at root s(NN) = 200 GeV. The measurement was made with respect to the reaction plane defined at high rapidities (vertical bar eta vertical bar = 3.1-3.9). From the result we have measured the v(2) of electrons from heavy flavor decay after subtraction of the v(2) of electrons from other sources such as photon conversions and Dalitz decay from light neutral mesons. We observe a nonzero single electron v(2) with a 90% confidence level in the intermediate-p(T) region. The precision of the present data set does not permit us to conclude definitively that heavy quarks exhibit thermalization with the transverse flow of the bulk matter.
|
|
| 7. |
- Adler, SS, et al.
(författare)
-
Measurement of transverse single-spin asymmetries for midrapidity production of neutral pions and charged hadrons in polarized p+p collisions at root s=200 GeV
- 2005
-
Ingår i: Physical Review Letters. - 1079-7114. ; 95
-
Tidskriftsartikel (refereegranskat)abstract
- Transverse single-spin asymmetries to probe the transverse-spin structure of the proton have been measured for neutral pions and nonidentified charged hadrons from polarized proton-proton collisions at midrapidity and root s = 200 GeV. The data cover a transverse momentum (pT) range 1.0-5.0 GeV/c for neutral pions and 0.5-5.0 GeV/c for charged hadrons, at a Feynman-x value of approximately zero. The asymmetries seen in this previously unexplored kinematic region are consistent with zero within errors of a few percent. In addition, the inclusive charged hadron cross section at midrapidity from 0.5 < P-T < 7.0 GeV/c is presented and compared to next-to-leading order perturbative QCD ( pQCD) calculations. Successful description of the unpolarized cross section above similar to 2 GeV/c suggests that pQCD is applicable in the interpretation of the asymmetry results in the relevant kinematic range.
|
|
| 8. |
- Adler, SS, et al.
(författare)
-
Midrapidity direct-photon production in p+p collisions at root s=200 GeV
- 2005
-
Ingår i: Physical Review D (Particles and Fields). - 0556-2821. ; 71:7
-
Tidskriftsartikel (refereegranskat)abstract
- A measurement of direct photons in p+p collisions at root s=200 GeV is presented. A photon excess above background from pi(0)->gamma+gamma, eta ->gamma+gamma and other decays is observed in the transverse momentum range 5.5 < p(T)< 7 GeV/c. The result is compared to a next-to-leading-order perturbative QCD calculation. Within errors, good agreement is found between the QCD calculation and the measured result.
|
|
| 9. |
- Adler, SS, et al.
(författare)
-
Production of phi mesons at midrapidity in root S-NN=200 GeVAu+Au collisions at relativistic energies
- 2005
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 72:1
-
Tidskriftsartikel (refereegranskat)abstract
- We present the results of phi meson production in the K+K- decay channel from Au+Au collisions at root s(NN) =200 GeV as measured at midrapidity by the PHENIX detector at Brookhaven National Laboratory's Relativistic Heavy Ion Collider. Precision resonance centroid and width values are extracted as a function of collision centrality. No significant variation from the Particle Data Group accepted values is observed, contrary to some model predictions. The phi transverse mass spectra are fitted with a linear exponential function for which the derived inverse slope parameter is seen to be constant as a function of centrality. However, when these data are fitted by a hydrodynamic model the result is that the centrality-dependent freeze-out temperature and the expansion velocity values are consistent with the values previously derived from fitting identified charged hadron data. As a function of transverse momentum the collisions scaled peripheral-to-central yield ratio R-CP for the phi is comparable to that of pions rather than that of protons. This result lends support to theoretical models that distinguish between baryons and mesons instead of particle mass for explaining the anomalous (anti) proton yield.
|
|
| 10. |
- Adler, S. S., et al.
(författare)
-
Dense-medium modifications to jet-induced hadron pair distributions in Au+Au collisions at root(NN)-N-S=200 GeV
- 2006
-
Ingår i: Physical Review Letters. - 1079-7114. ; 97:5
-
Tidskriftsartikel (refereegranskat)abstract
- Azimuthal correlations of jet-induced high-p(T) charged hadron pairs are studied at midrapidity in Au+Au collisions at root s(NN)=200 GeV. The distribution of jet-associated partner hadrons (1.0 < p(T)< 2.5 GeV/c) per trigger hadron (2.5 < p(T)< 4.0 GeV/c) is found to vary with collision centrality, in both shape and yield, indicating a significant effect of the nuclear collision medium on the jet fragmentation process.
|
|
| 11. |
- Adler, S. S., et al.
(författare)
-
Detailed study of high-p(T) neutral pion suppression and azimuthal anisotropy in Au plus Au collisions at root s(NN) =200 GeV
- 2007
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 76:3
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of neutral pion (pi(0)) production at midrapidity in root s(NN)=200 GeV Au+Au collisions as a function of transverse momentum, p(T), collision centrality, and angle with respect to reaction plane are presented. The data represent the final pi(0) results from the PHENIX experiment for the first RHIC Au+Au run at design center-of-mass energy. They include additional data obtained using the PHENIX Level-2 trigger with more than a factor of 3 increase in statistics over previously published results for p(T)>6 GeV/c. We evaluate the suppression in the yield of high-p(T) pi(0)'s relative to pointlike scaling expectations using the nuclear modification factor R-AA. We present the p(T) dependence of R-AA for nine bins in collision centrality. We separately integrate R-AA over larger p(T) bins to show more precisely the centrality dependence of the high-p(T) suppression. We then evaluate the dependence of the high-p(T) suppression on the emission angle Delta phi of the pions with respect to event reaction plane for seven bins in collision centrality. We show that the yields of high-p(T) pi(0)'s vary strongly with Delta phi, consistent with prior measurements 1,2. We show that this variation persists in the most peripheral bin accessible in this analysis. For the peripheral bins we observe no suppression for neutral pions produced aligned with the reaction plane, whereas the yield of pi(0)'s produced perpendicular to the reaction plane is suppressed by a factor of similar to 2. We analyze the combined centrality and Delta phi dependence of the pi(0) suppression in different p(T) bins using different possible descriptions of parton energy loss dependence on jet path-length averages to determine whether a single geometric picture can explain the observed suppression pattern.
|
|
| 12. |
- Adler, S. S., et al.
(författare)
-
Evidence for a long-range component in the pion emission source in Au plus Au collisions at root s(NN)=200 GeV
- 2007
-
Ingår i: Physical Review Letters. - 1079-7114. ; 98:13
-
Tidskriftsartikel (refereegranskat)abstract
- Emission source functions are extracted from correlation functions constructed from charged pions produced at midrapidity in Au+Au collisions at s(NN)=200 GeV. The source parameters extracted from these functions at low k(T) give first indications of a long tail for the pion emission source. The source extension cannot be explained solely by simple kinematic considerations. The possible role of a halo of secondary pions from resonance emissions is explored.
|
|
| 13. |
- 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.
|
|
| 14. |
|
|
| 15. |
- Adler, S. S., et al.
(författare)
-
Measurement of single muons at forward rapidity in p+p collisions at root s=200 GeV and implications for charm production
- 2007
-
Ingår i: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-2368. ; 76:9
-
Tidskriftsartikel (refereegranskat)abstract
- Muon production at forward rapidity (1.5 <=|eta|<= 1.8) has been measured by the PHENIX experiment over the transverse momentum range 1 <= p(T)<= 3 GeV/c in root s=200 GeV p+p collisions at the Relativistic Heavy Ion Collider. After statistically subtracting contributions from light hadron decays an excess remains which is attributed to the semileptonic decays of hadrons carrying heavy flavor, i.e. charm quarks or, at high p(T), bottom quarks. The resulting muon spectrum from heavy flavor decays is compared to PYTHIA and a next-to-leading-order perturbative QCD calculation. PYTHIA is used to determine the charm quark spectrum that would produce the observed muon excess. The corresponding differential cross section for charm quark production at forward rapidity is determined to be d sigma(c (c) over bar)/dy|(y=1.6)=0.243 +/- 0.013(stat.)+/- 0.105(data syst.)(-0.087)(+0.049)(PYTHIA syst.) mb.
|
|
| 16. |
- Adler, SS, et al.
(författare)
-
Single electrons from heavy-flavor decays in p + p collisions at root s=200 GeV
- 2006
-
Ingår i: Physical Review Letters. - 1079-7114. ; 96:3
-
Tidskriftsartikel (refereegranskat)abstract
- The invariant differential cross section for inclusive electron production in p+p collisions at root s=200 GeV has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over the transverse momentum range 0.4 <= p(T) <= 5.0 GeV/c in the central rapidity region (vertical bar eta vertical bar <= 0.35). The contribution to the inclusive electron spectrum from semileptonic decays of hadrons carrying heavy flavor, i.e., charm quarks or, at high p(T), bottom quarks, is determined via three independent methods. The resulting electron spectrum from heavy-flavor decays is compared to recent leading and next-to-leading order perturbative QCD calculations. The total cross section of charm quark-antiquark pair production is determined to be sigma(c (c) over bar) = 0.92 +/- 0.15(stat) +/- 0.54(syst) mb.
|
|
| 17. |
- Cai, G-H, et al.
(författare)
-
Quantitative PCR analysis of fungal DNA in Swedish day care centers and comparison with building characteristics and allergen levels
- 2009
-
Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 19:5, s. 392-400
-
Tidskriftsartikel (refereegranskat)abstract
- Sweden has had allergen-avoidance day care centers (AADCs) since 1979. The aim of this study was to measure fungal DNA by quantitative polymerase chain reaction (qPCR), a new method, in AADCs and ordinary day care centers (ODCs) and examine associations between allergen levels and building characteristics. Dust samples were collected by swabbing doorframes, vacuum-cleaning, and using Petri dishes. In total, 11 AADCs and 11 ODCs were studied (70 rooms). Total fungal DNA, measured by qPCR in the swab dust, was detected in 89%, Aspergillus or Penicillium (Asp/Pen) DNA in 34%, and Stachybotrys chartarum DNA in 6% of the rooms. Total fungal DNA was significantly higher in rooms with linoleum floor (P = 0.02), textile carpets (P = 0.03), reported dampness/molds (P = 0.02) and reported odor (P < 0.001) in the buildings, and significantly lower in wooden facade buildings (P = 0.003). Reported odor was related to the amount of sieved fine dust, reported dampness/molds and type of building construction. Total fungal DNA was related to cat, dog, horse and total allergen levels (P = 0.003) in the day care centers. In conclusion, total fungal DNA is related to reported dampness/molds, reported odor, and type of wall construction. The association between fungal and allergen contamination indicated a general 'hygiene factor' related to biological contaminants. Practical Implications The associations between fungal DNA, reported dampness/molds, and odor support the view that buildings with odor problems should be investigated for possible hidden fungal growth. There is a need to measure fungal biomass in different types of building constructions by monitoring fungal DNA. Analysis of fungal DNA with quantitative PCR can be a fast and practical way to study indoor fungal contamination. Swabbing dust from the doorframe of the main entrance to the room can be a convenient method of sampling dust for fungal DNA analysis. The high prevalence of reported dampness/molds and the common occurrence of fungal DNA indicate the need to improve the indoor environment of Swedish day care centers.
|
|
| 18. |
|
|
| 19. |
|
|
| 20. |
- Kim, Jeong-Lim, 1981-
(författare)
-
Environmental Factors in Relation to Asthma and Respiratory Symptoms among Schoolchildren in Sweden and Korea
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis studied environmental factors in relation to asthma and respiratory symptoms among schoolchildren in two countries. In Sweden, 1014 pupils (5-14 year) in 8 schools participated. Wheeze was reported by 7.8%, current asthma by 5.9%, doctor-diagnosed asthma by 7.7%, cat allergy by 6.8% and dog allergy by 4.8%. Current asthma was less common among those consuming more fresh milk and fish. Doctor-diagnosed asthma was less common among those consuming olive oil. Cat, dog and horse allergens were common in settled dust and related to respiratory symptoms. Pupils consuming butter and fresh milk had less respiratory symptoms in relation to allergen exposure. In schools with increased levels of microbial volatile organic compounds and selected plasticizers (Texanol and TXIB) asthma and respiratory symptoms were more common.In Korea, 2365 pupils (9-11 year) in 12 schools participated (96%). In total, wheeze was reported by 8.0%, current asthma by 5.7%, doctor-diagnosed asthma by 5.4%, cat allergy by 2.6% and dog allergy by 4.9%. Contamination of dog and mite (Dermatophagoides farinae) allergen was common while cat allergen was uncommon. Remodelling, changing floor and building dampness at home were positively associated with asthma and respiratory symptoms. The strongest associations were found for floor dampness. Indoor/outdoor concentration of NO2, formaldehyde and ultrafine particles (UFP) at schools were positively associated with asthma and respiratory symptoms. When comparing Sweden and Korea, Korean pupils had more breathlessness and asthma but reported less cat and pollen allergy. Swedish schools had CO2-levels below 1000 ppm, while most Korean schools exceeded this standard. Since both home and school environment may affect pupil’s asthma and respiratory symptoms, air quality should be an important health issue. Moreover, changes in dietary habits may be beneficial to decrease asthma and allergies. Furthermore, interaction between diet and environment needs to be further investigated.
|
|
| 21. |
- Kim, Jeong-Lim, et al.
(författare)
-
Indoor molds, bacteria, microbial volatile organic compounds and plasticizers in schools : associations with asthma and respiratory symptoms in pupils
- 2007
-
Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 17:2, s. 153-163
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated asthma and atopy in relation to microbial and plasticizer exposure. Pupils in eight primary schools in Uppsala (Sweden) answered a questionnaire, 1014 (68%) participated. Totally, 7.7% reported doctor-diagnosed asthma, 5.9% current asthma, and 12.2% allergy to pollen/pets. Wheeze was reported by 7.8%, 4.5% reported daytime breathlessness, and 2.0% nocturnal breathlessness. Measurements were performed in 23 classrooms (May–June), 74% had <1000 ppm CO2 indoors. None had visible mold growth or dampness. Mean total microbial volatile organic compound (MVOC) concentration was 423 ng/m3 indoors and 123 ng/m3 outdoors. Indoor concentration of TMPD-MIB (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, Texanol) and TMPD-DIB (2,2,4-trimethyl-1,3-pentanediol diisobutyrate, TXIB), two common plasticizers, were 0.89 and 1.64 μg/m3, respectively. MVOC and plasticizer concentration were correlated (r = 0.5; P < 0.01). Mold concentration was 360 cfu/m3 indoors and 980 cfu/m3 outdoors. At higher indoor concentrations of total MVOC, nocturnal breathlessness (P < 0.01) and doctor-diagnosed asthma (P < 0.05) were more common. Moreover, there were positive associations between nocturnal breathlessness and 3-methylfuran (P < 0.01), 3-methyl-1-butanol (P < 0.05), dimethyldisulfide (P < 0.01), 2-heptanone (P < 0.01), 1-octen-3-ol (P < 0.05), 3-octanone (P < 0.05), TMPD-MIB (P < 0.05), and TMPD-DIB (P < 0.01). TMPD-DIB was positively associated with wheeze (P < 0.05), daytime breathlessness (P < 0.05), doctor-diagnosed asthma (P < 0.05), and current asthma (P < 0.05). In conclusion, exposure to MVOC and plasticizers at school may be a risk factor for asthmatic symptoms in children.
|
|
| 22. |
- Kim, Jeong-Lim, et al.
(författare)
-
Respiratory symptoms, asthma and allergen levels in schools : comparison between Korea and Sweden
- 2007
-
Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 17:2, s. 122-129
-
Tidskriftsartikel (refereegranskat)abstract
- We studied reports on respiratory symptoms, asthma and atopic sensitisation in relation to allergen contamination in Korean schools and compared with data from a previous Swedish study performed in eight primary schools. Korean pupils (n = 2365) in 12 primary schools first completed a questionnaire. Then airborne and settled dust were collected from 34 classrooms and analyzed for allergens by ELISA. In both countries, boys reported more symptoms. The prevalence of wheeze was similar, while daytime [odds ratio (OR) = 14.0, 95% confidence interval (CI) = 9.0–21.9] and nocturnal breathlessness (OR = 3.1, 95% CI = 1.5–6.4) were much higher among Korean students. In Korean schools, dog allergen (Can f 1) was the most common followed by mite allergen (Der f 1), while cat (Fel d 1), dog, and horse allergen (Equ cx) were abundant in Sweden. Moreover, CO2 levels were high in most Korean schools (range 907–4113 ppm). There was an association between allergen levels in dust and air samples, and number of pet-keepers in the classrooms. In conclusion, allergen contamination in Korean schools may be an important public issue.
|
|
