17907752
Observation of hypertritons in Au+Au collisions at \sqrt{s_{NN}} = 200 GeV
We report preliminary results of hypertriton observation in heavy-ion collisions at RHIC. We have identified 157 +- 30 candidates in the current sample containing ~10^8 Au+Au events at \sqrt{s_{NN}} = 200 GeV. The production rate of hypertriton is close to that of helium 3. No extra penalty factor is observed for hypertriton, in contrast to results observed at the AGS.
18805981
System size and energy dependence of phi meson production at RHIC
We present a system size and energy dependence of meson production in Cu + Cu and Au + Au collisions at GeV and 200 GeV measured by the STAR experiment at RHIC. We find that the number of participant scaled meson yields in heavy-ion collisions over that of p + p collisions are larger than 1 and increase with collision energy. We compare the results with those of open-strange particles and discuss the physics implication.
122417032
Hypernucleus physics at RHIC
Abstract We report recent progress in hypernucleus studies measured by the STAR collaboration at the Relativistic Heavy Ion Collider. We show a preliminary hypertriton measurement from our current event sample and discuss the next step for this project.
118394652
Dust, Ice, and Gas In Time (DIGIT) Herschel program first results A full PACS-SED scan of the gas line emission in protostar DK Chamaeleontis
Aims. We aim to study the composition and energetics of the circumstellar material of DK Cha, an intermediate-mass star in transition from an 
embedded configuration to a star plus disk stage, during this pivotal stage of its evolution. 
Methods. Using the range scan mode of PACS on the Herschel Space Observatory, we obtained a spectrum of DK Cha from 55 to 210 μm as part 
of the DIGIT key program. 
Results. Almost 50 molecular and atomic lines were detected, many more than the 7 lines detected in ISO-LWS. Nearly the entire ladder of CO 
from J = 14–13 to 38–37 (E_u/k = 4080 K), water from levels as excited as J_(K−1 K+1) = 7_(07) (E_u/k = 843 K), and OH lines up to E_u/k = 290 K were 
detected. 
Conclusions. The continuum emission in our PACS SED scan matches the flux expected by a model consisting of a star, a surrounding disk of 
0.03 M_⊙, and an envelope of a similar mass, supporting the suggestion that the object is emerging from its main accretion stage. Molecular, atomic, 
and ionic emission lines in the far-infrared reveal the outflow’s influence on the envelope. The inferred hot gas may be photon-heated, but some 
emission may be caused by C-shocks in the walls of the outflow cavity.
123049469
Directed flow measurements from STAR
STAR measurements of v1 for identified particles for Au+Au collisions at = 200 GeV are presented. A negative v1 slope is observed for pions, protons, antiprotons and kaons (K0S) in 10-70% central collisions. For pion v1 slope, the comparison between the current result and available models (RQMD, UrQMD, AMPT, QGSM and hydro model with a tilted source) is made. In 5-30% central collisions, surprisingly sizable difference between v1 of protons and antiprotons is observed. The centrality and energy dependence of proton v1 are also presented. The charged hadron v1 for Cu+Cu collisions at = 22.4 GeV is measured and compared with results obtained previously.
115761963
Comment on "Subleading Corrections to Parity Violating Pion Photoproduction"
In a recent preprint, hep-ph/0012253, Zhu et al. calculated a part of the next-to-leading order corrections to parity-violating pion photoproduction (pol)gamma p-> pi^+ n in heavy-baryon chiral perturbation theory. They claim they have found the contribution as large as the leading-order. If correct, the process will not be a clean way to extract the longest range PV pion-nucleon coupling constant h_{\pi NN}^(1), as was asserted in our previous publications (hep-ph/0011230, nucl-th/0011100). In this comment we show that there is no solid evidence to support Zhu et al.'s claim. Moreover, we show that the subleading parity-violating coupling h_V cannot be extracted from observables at the order of interest based on the formalism of effective field theory.
122191299
Directed flow of identified particles from Au+Au collisions at RHIC
We present and K0s directed flow in Au+Au collisions at GeV and GeV, measured by the STAR experiment. To improve the event plane resolution, we determine the event plane from sideward deflection of spectator neutrons measured by STAR's shower maximum detector at zero degree calorimeters (ZDC-SMD), together with tracks reconstructed with the forward time projection chambers (FTPC). Our result will be presented as a function of pseudorapidity, transverse momentum and centrality.
7181580
Leading chiral contributions to the spin structure of the proton.
The leading chiral contributions to the quark and gluon components of the proton spin are calculated using heavy-baryon chiral perturbation theory. Similar calculations are done for the moments of the generalized parton distributions relevant to the quark and gluon angular momentum densities. These results provide useful insight into the role of pions in the spin structure of the nucleon and can serve as a guide for extrapolating lattice QCD calculations at large quark masses to the chiral limit.
119512566
Drell-Hearn-Gerasimov sum-rule for the deuteron in nuclear effective field theory
Abstract The Drell–Hearn–Gerasimov sum rule for the deuteron is studied in nuclear effective field theory. The low-energy theorem for the spin-dependent Compton amplitude f 1 ( ω ) is derived to the next-to-leading order in low-energy expansion. The spin-dependent photo-disintegration cross-section σ P − σ A is calculated to the same order, and its contribution to the dispersive integral is evaluated.