Dimuon results in PbPb and pp collisions in CMS

The LHC offers unique opportunities for studying the properties of hot QCD matter created in Pb+Pb collisions at extreme temperatures and very low parton momentum fractions. With its high precision, large acceptance for tracking and calorimetry, and a trigger scheme that allows analysis of each minimum bias Pb+Pb event, CMS is fully equipped to measure dimuons in the high multiplicity environment of Pb+Pb collisions. Such probes are especially relevant since they are produced at early times and propagate through the medium, mapping its evolution. The capabilities of the CMS experiment to study dimuon production in pp and Pb+Pb collisions based on the 2010 LHC runs will be reviewed. CMS is able to measure primary and secondary J/psi, as well as the three Upsilon states. Quarkonia results at sqrt(s)=2.76 TeV in pp and Pb+Pb will be presented, including a tantalizing observation of suppression of the Upsilon excited states. The Z0 boson inclusive and differential measurement as a probe of the initial state will be described.Comment: 3 pages, 4 figures. To appear in the proceedings of PANIC 201

Antecedentes del Servicio Meteorológico en España: la correspondencia entre Arcimis y Pujazón

Augusto Arcimis Wehrle, nacido en Sevilla el 4 de Diciembre de 1844, fue nombrado en 1888 director de la institución que actualmente se denomina Agencia Estatal de Meteorología, creada por Real Decreto de 1887 con el nombre de Instituto Central Meteorológico (ICM). Se convirtió así en el primer meteorólogo profesional con plena dedicación en España. Arcimis cursó el bachillerato en Cádiz a donde se había trasladado su familia cuando era niño. Allí se doctoró en Farmacia y, gracias a la fortuna familiar viajó por toda Europa y llegó a dominar varias lenguas. De vuelta a Cádiz se dedicó a diversas actividades relacionadas con los negocios familiares, pero su interés principal era ya el estudio de la Astronomía y la Meteorología, aficiones en las que se inició durante una larga estancia en Londres y que desarrolló como autodidacta durante muchos años. En su casa de Cádiz y luego en una finca que le dejó su amigo José Macpherson en Chiclana instaló un observatorio astronómico y meteorológico bastante completo

Mid-rapidity π±\pi^\pm, K±K^\pm, and pˉ\bar{p} spectra and particle ratios from STAR

Results are presented on $\pi^\pm$, $K^\pm$, and $\bar{p}$ transverse mass spectra and particle multiplicity ratios at mid-rapidity in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$=130 and 200 GeV and in p+p collisions at $\sqrt{s}$=200 GeV. Comparisons are made to results from lower energies. The bulk properties of the collision inferred from these results are discussed.Comment: 4 pages, 3 figures, Talk presented at Quark Matter 2002, Nantes, France, July 200

STAR Results on High Transverse Momentum, Heavy Flavor and Electromagnetic Probes

We summarize here recent results from the STAR collaboration focusing on processes involving large momentum transfers. Measurements of angular correlations of di-hadrons are explored in both the pseudorapidity (eta) and azimuthal (phi) projections. In central Au+Au, an elongated structure is found in the eta projection which persists up to the highest measured pT. After quantifying the particle yield in this structure and subtracting it from the near-side yield, we observe that the remainder exhibits a behavior strikingly similar to that of the near-side yield in d+Au. For heavy flavor production, using electron-hadron correlations in p+p collisions, we obtain an estimate of the b-quark contribution to the non-photonic electrons in the pT region 3-6 GeV/c, and find it consistent with FONLL calculations. Together with the observed suppression of non-photonic electrons in Au+Au, this strongly suggests suppression of b-quark production in Au+Au collisions. We discuss results on the mid-rapidity Upsilon cross-section in p+p collisions. Finally, we present a proof-of-principle measurement of photon-hadron correlations in p+p collisions, paving the way for the tomographic study of the matter produced in central Au+Au via gamma-jet measurements.Comment: 8 pages, 4 figures. Proceedings of "Quark Matter 2006", 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collision

The STAR Time Projection Chamber: A Unique Tool for Studying High Multiplicity Events at RHIC

The STAR Time Projection Chamber (TPC) is used to record collisions at the Relativistic Heavy Ion Collider (RHIC). The TPC is the central element in a suite of detectors that surrounds the interaction vertex. The TPC provides complete coverage around the beam-line, and provides complete tracking for charged particles within +- 1.8 units of pseudo-rapidity of the center-of-mass frame. Charged particles with momenta greater than 100 MeV/c are recorded. Multiplicities in excess of 3,000 tracks per event are routinely reconstructed in the software. The TPC measures 4 m in diameter by 4.2 m long, making it the largest TPC in the world.Comment: 28 pages, 11 figure

Measurement of Elliptic Flow of Light Nuclei at √\u3cem\u3e\u3csup\u3eS\u3c/sup\u3e\u3csub\u3eNN\u3c/sub\u3e\u3c/em\u3e = 200, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV at the BNL Relativistic Heavy Ion Collider

We present measurements of second-order azimuthal anisotropy (υ2) at midrapidity (|y| \u3c 1.0) for light nuclei d, t, 3He (for ⎷sNN = 200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The υ2 for these light nuclei produced in heavy-ion collisions is compared with those for p and p¯. We observe mass ordering in nuclei υ2 (pT) at low transverse momenta (pT \u3c 2.0 GeV/c). We also find a centrality dependence of υ2 for d and d¯. The magnitude of υ2 for t and 3He agree within statistical errors. Light-nuclei υ2 are compared with predictions from a blast-wave model. Atomic mass number (A) scaling of light-nuclei υ2 (pT) seems to hold for pT/A \u3c 1.5 GeV/c. Results on light-nuclei υ2 from a transport-plus-coalescence model are consistent with the experimental measurements

Centrality Dependence of Identified Particle Elliptic Flow in Relativistic Heavy Ion Collisions at √\u3cem\u3e\u3csup\u3es\u3c/sup\u3e\u3csub\u3eNN\u3c/sub\u3e\u3c/em\u3e = 7.7–62.4 GeV

Elliptic flow (υ2) values for identified particles at midrapidity in Au + Au collisions measured by the STAR experiment in the Beam Energy Scan at the Relativistic Heavy Ion Collider at √sNN = 7.7– 62.4 GeV are presented for three centrality classes. The centrality dependence and the data at √sNN = 14.5 GeV are new. Except at the lowest beam energies, we observe a similar relative υ2 baryon-meson splitting for all centrality classes which is in agreement within 15% with the number-of-constituent quark scaling. The larger υ2 for most particles relative to antiparticles, already observed for minimum bias collisions, shows a clear centrality dependence, with the largest difference for the most central collisions. Also, the results are compared with a multiphase transport (AMPT) model and fit with a blast wave model

\u3cem\u3eJ/ψ\u3c/em\u3e Production at Low Transverse Momentum in \u3cem\u3ep\u3c/em\u3e + \u3cem\u3ep\u3c/em\u3e and \u3cem\u3ed\u3c/em\u3e + Au Collisions at √\u3cem\u3e\u3csup\u3es\u3c/sup\u3e\u3csub\u3eNN\u3c/sub\u3e\u3c/em\u3e = 200 GeV

We report on the measurement of J/ψ production in the dielectron channel at midrapidity (|y| \u3c 1) in p + p and d + Au collisions at √sNN = 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider. The transverse momentum pTspectra in p + p for pT \u3c 4 GeV/c and d + Au collisions for pT \u3c 3 GeV/c are presented. These measurements extend the STAR coverage for J/ψ production in p + p collisions to low pT. The ⟨p2T⟩ from the measured J/ψ invariant cross section in p + p and d + Au collisions are evaluated and compared to similar measurements at other collision energies. The nuclear modification factor for J/ψ is extracted as a function of pT and collision centrality in d + Au and compared to model calculations using the modified nuclear parton distribution function and a final-state J/ψ nuclear absorption cross section