排序方式: 共有45条查询结果,搜索用时 15 毫秒
1.
Abelev BI Aggarwal MM Ahammed Z Anderson BD Arkhipkin D Averichev GS Bai Y Balewski J Barannikova O Barnby LS Baudot J Baumgart S Belaga VV Bellingeri-Laurikainen A Bellwied R Benedosso F Betts RR Bhardwaj S Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Blyth SL Bombara M Bonner BE Botje M Bouchet J Brandin AV Bravar A Burton TP Bystersky M Cadman RV Cai XZ Caines H Calderón de la Barca Sánchez M Callner J Catu O Cebra D Chajecki Z Chaloupka P Chattopadhyay S Chen HF Chen JH 《Physical review letters》2007,99(11):112301
We present first measurements of the phi-meson elliptic flow (v2(pT)) and high-statistics pT distributions for different centralities from radical sNN=200 GeV Au+Au collisions at RHIC. In minimum bias collisions the v2 of the phi meson is consistent with the trend observed for mesons. The ratio of the yields of the Omega to those of the phi as a function of transverse momentum is consistent with a model based on the recombination of thermal s quarks up to pT approximately 4 GeV/c, but disagrees at higher momenta. The nuclear modification factor (R CP) of phi follows the trend observed in the K S 0 mesons rather than in Lambda baryons, supporting baryon-meson scaling. These data are consistent with phi mesons in central Au+Au collisions being created via coalescence of thermalized s quarks and the formation of a hot and dense matter with partonic collectivity at RHIC. 相似文献
2.
Adams J Adler C Aggarwal MM Ahammed Z Amonett J Anderson BD Anderson M Arkhipkin D Averichev GS Badyal SK Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellwied R Berger J Bezverkhny BI Bhardwaj S Bhaskar P Bhati AK Bichsel H Billmeier A Bland LC Blyth CO Bonner BE Botje M Boucham A Brandin A Bravar A Cadman RV Cai XZ Caines H Calderón de la Barca Sánchez M Carroll J Castillo J Castro M Cebra D Chaloupka P Chattopadhyay S Chen HF Chen Y Chernenko SP Cherney M Chikanian A Choi B 《Physical review letters》2004,92(17):171801
Measurements of the production of forward high-energy pi(0) mesons from transversely polarized proton collisions at sqrt[s]=200 GeV are reported. The cross section is generally consistent with next-to-leading order perturbative QCD calculations. The analyzing power is small at x(F) below about 0.3, and becomes positive and large at higher x(F), similar to the trend in data at sqrt[s]< or =20 GeV. The analyzing power is in qualitative agreement with perturbative QCD model expectations. This is the first significant spin result seen for particles produced with p(T)>1 GeV/c at a polarized proton collider. 相似文献
3.
Adams J Aggarwal MM Ahammed Z Amonett J Anderson BD Arkhipkin D Averichev GS Badyal SK Bai Y Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellwied R Berger J Bezverkhny BI Bharadwaj S Bhasin A Bhati AK Bhatia VS Bichsel H Billmeier A Bland LC Blyth CO Bonner BE Botje M Boucham A Brandin AV Bravar A Bystersky M Cadman RV Cai XZ Caines H Calderón de la Barca Sánchez M Carroll J Castillo J Cebra D Chajecki Z Chaloupka P Chattopdhyay S Chen HF Chen Y Cheng J Cherney M Chikanian A 《Physical review letters》2004,93(25):252301
Results on high transverse momentum charged particle emission with respect to the reaction plane are presented for Au + Au collisions at square root s(NN)=200 GeV. Two- and four-particle correlations results are presented as well as a comparison of azimuthal correlations in Au + Au collisions to those in p + p at the same energy. The elliptic anisotropy v(2) is found to reach its maximum at p(t) approximately 3 GeV/c, then decrease slowly and remain significant up to p(t) approximately 7-10 GeV/c. Stronger suppression is found in the back-to-back high-p(t) particle correlations for particles emitted out of plane compared to those emitted in plane. The centrality dependence of v(2) at intermediate p(t) is compared to simple models based on jet quenching. 相似文献
4.
P. Cadman G. Gossedge J.D. Scott 《Journal of Electron Spectroscopy and Related Phenomena》1978,13(1):1-6
Relative inelastic mean free paths (λ) for 1000-eV electrons have been determined for a number of polymers and other materials (relative to 967-eV electrons in graphite) using X-ray photoelectron spectroscopy. The carbon-containing compounds were found to have values of λ in the range 3.7–7.1 nm while λ (silicon) was 3.0 nm i.e. 1.2–2.3 times and 1.0 times that for graphite. 相似文献
5.
Cuttlebone is a natural material possessing the multifunctional properties of high porosity, high flexural stiffness and compressive strength, making it a fine example of design optimization of cellular structures created by nature. Examination of cuttlebone using scanning electron micros- copy (SEM) reveals an approximately periodic microstruc- ture, appropriate for computational characterization using direct homogenization techniques. In this paper, volume fractions and stiffness tensors were determined based on two different unit cell models that were extracted from two different cuttlefish samples. These characterized results were then used as the target values in an inverse homogenization procedure aiming to re-generate microstructures with the same properties as cuttlebone. Unit cells with similar topologies to the original cuttlebone unit cells were achieved, attaining the same volume fraction (i.e. bulk density) and the same (or very close) stiffness tensor. In addition, a range of alternate unit cell topologies were achieved also attaining the target properties, revealing the non-unique nature of this inverse homogenization problem. 相似文献
6.
We consider a collapsing spherically symmetric inhomogeneous dust cloud in higher dimensional space-time. We show that the
central singularity of collapse can be a strong curvature or a weak curvature naked singularity depending on the initial density
distribution. 相似文献
7.
Abelev BI Aggarwal MM Ahammed Z Anderson BD Anderson M Arkhipkin D Averichev GS Bai Y Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellingeri-Laurikainen A Bellwied R Benedosso F Bhardwaj S Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Blyth SL Bonner BE Botje M Bouchet J Brandin AV Bravar A Burton TP Bystersky M Cadman RV Cai XZ Caines H Calderón de la Barca Sánchez M Castillo J Catu O Cebra D Chajecki Z Chaloupka P Chattopadhyay S Chen HF Chen JH Cheng J 《Physical review letters》2006,97(15):152301
Transverse momentum spectra of pi+/-, p, and p up to 12 GeV/c at midrapidity in centrality selected Au + Au collisions at square root sNN=200 GeV are presented. In central Au + Au collisions, both pi +/- and p(p) show significant suppression with respect to binary scaling at pT approximately >4 GeV/c. Protons and antiprotons are less suppressed than pi+/-, in the range 1.5 approximately < pT approximately < 6 GeV/c. The pi-/pi+ and p/p ratios show at most a weak pT dependence and no significant centrality dependence. The p/pi ratios in central Au + Au collisions approach the values in p + p and d + Au collisions at pT approximately >5 GeV/c. The results at high pT indicate that the partonic sources of pi+/-, p, and p have similar energy loss when traversing the nuclear medium. 相似文献
8.
Adams J Aggarwal MM Ahammed Z Amonett J Anderson BD Arkhipkin D Averichev GS Badyal SK Bai Y Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellingeri-Laurikainen A Bellwied R Berger J Bezverkhny BI Bharadwaj S Bhasin A Bhati AK Bhatia VS Bichsel H Bielcik J Bielcikova J Billmeier A Bland LC Blyth CO Blyth SL Bonner BE Botje M Boucham A Bouchet J Brandin AV Bravar A Bystersky M Cadman RV Cai XZ Caines H Sánchez MC Catu O Cebra D Chajecki Z Chaloupka P Chattopadhyay S Chen HF 《Physical review letters》2006,97(15):152302
Measurements of the production of forward pi0 mesons from p + p and d + Au collisions at square root sNN=200 GeV are reported. The p + p yield generally agrees with next-to-leading order perturbative QCD calculations. The d + Au yield per binary collision is suppressed as eta increases, decreasing to approximately 30% of the p + p yield at eta =4.00, well below shadowing expectations. Exploratory measurements of azimuthal correlations of the forward pi0 with charged hadrons at eta approximately 0 show a recoil peak in p + p that is suppressed in d + Au at low pion energy. These observations are qualitatively consistent with a saturation picture of the low-x gluon structure of heavy nuclei. 相似文献
9.
Adams J Aggarwal MM Ahammed Z Amonett J Anderson BD Anderson M Arkhipkin D Averichev GS Bai Y Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellingeri-Laurikainen A Bellwied R Bezverkhny BI Bhardwaj S Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Blyth CO Blyth SL Bonner BE Botje M Bouchet J Brandin AV Bravar A Bystersky M Cadman RV Cai XZ Caines H Calderón de la Barca Sánchez M Castillo J Catu O Cebra D Chajecki Z Chaloupka P Chattopadhyay S Chen HF Chen JH 《Physical review letters》2006,97(16):162301
The STAR Collaboration at the Relativistic Heavy Ion Collider reports measurements of azimuthal correlations of high transverse momentum (pT) charged hadrons in Au+Au collisions at higher pT than reported previously. As (pT) is increased, a narrow, back-to-back peak emerges above the decreasing background, providing a clear dijet signal for all collision centralities studied. Using these correlations, we perform a systematic study of dijet production and suppression in nuclear collisions, providing new constraints on the mechanisms underlying partonic energy loss in dense matter. 相似文献
10.
The scattering of incident plane elastic waves by a varietyof different defects that lie upon a fluid-solid interface isconsidered here using matched asymptotic expansions. The expansionscheme is developed in terms of a parameter , the ratio of typicaldefect length scale to a typical wavelength of the incidentfield, taken to be small. Three different canonical situations occur and these are illustratedvia three specific examples treated here: a rigid strut, anedge crack, and a rigid strip. In each case the leading-ordermatching is performed to identify the leading-order contributionof the defect to the acoustic field in the far field. In particular,each defect is identified with a source of dipole response ininterfacial stress of displacement. It is shown in the limit as s<<s1 that in the inner problemsthe fluid and solid pieces uncouple in a particularly convenientmanner allowing analytical solutions to be deduced. These arethen matched with appropriate outer solutions. 相似文献