Mon·Oct 10, 2011Monday·October 10, 2011

1. 01*

   Probing Hot and Dense Nuclear Matter with Particle Correlations and Jets at RHIC

   Hua Pei🇺🇸

   The hot and dense medium created at RHIC, called Quark and Gluon Plasma (QGP) has been a hot topic in the last ten years. Due to the high multiplicities in such heavy-ion collision events, particle correlations using either trigger particles, or fully-reconstructed jets, become not only useful but necessary, in addition to the single particle observables. In this paper the most recent work studying this medium will be shown, including both on bulk properties and tagged events.

   nucl-ex0 citations
2. 02*

   Jet Studies in STAR via 2+1 Correlations

   Hua Pei🇺🇸

   This paper reports analysis on jet-medium interactions and di-jet surface emission bias at RHIC, based on a new multi-hadron correlation technique called \texttt{2+1} where back-to-back high $p_T$ hadron triggers work as proxy of di-jets. In contrast with traditional correlations with single triggers, the associated hadron distributions and spectra at both trigger sides show no evident modification from d+Au to central Au+Au collisions. This observation stands for both cases when triggers pairs are symmetric($p_T>$5GeV/$c$ vs. $p_T>$4GeV/$c$) or asymmetric($E_T>$10GeV/$c$ vs. $p_T>$4GeV/$c$).

   nucl-ex0 citations
3. 03*

   An Improved Search for the Neutron Electric Dipole Moment

   M. Burghoff🇩🇪 · A. Schnabel🇩🇪 · G. Ban🇫🇷 · T. Lefort🇫🇷 · Y. Lemiere🇫🇷 · O. Naviliat-Cuncic🇫🇷 · E. Pierre🇫🇷 · G. Quemener🇺🇸 · J. Zejma🇵🇱 · M. Kasprzak🇨🇭 · P. Knowles🇨🇭 · A. Weis🇨🇭 and 25 other authors

   A permanent electric dipole moment of fundamental spin-1/2 particles violates both parity (P) and time re- versal (T) symmetry, and hence, also charge-parity (CP) symmetry since there is no sign of CPT-violation. The search for a neutron electric dipole moment (nEDM) probes CP violation within and beyond the Stan- dard Model. The experiment, set up at the Paul Scherrer Institute (PSI), an improved, upgraded version of the apparatus which provided the current best experimental limit, dn < 2.9E-26 ecm (90% C.L.), by the RAL/Sussex/ILL collaboration: Baker et al., Phys. Rev. Lett. 97, 131801 (2006). In the next two years we aim to improve the sensitivity of the apparatus to sigma(dn) = 2.6E-27 ecm corresponding to an upper limit of dn < 5E-27 ecm (95% C.L.), in case for a null result. In parallel the collaboration works on the design of a new apparatus to further increase the sensitivity to sigma(dn) = 2.6E-28 ecm.

   nucl-exphysics.ins-det12 citations
4. 04*

   Level density of 2+ states in 40Ca from high energy-resolution (p,p') experiments

   I. Usman (1,2)🇿🇦 · Z. Buthelezi (1)🇿🇦 · J. Carter (2)🇿🇦 · G. R. J. Cooper (3)🇿🇦 · R. W. Fearick (4)🇿🇦 · S. V. Förtsch (1)🇿🇦 · H. Fujita (1,2)🇿🇦 · Y. Kalmykov (5)🇩🇪 · P. von Neumann-Cosel (5)🇩🇪 · R. Neveling (1)🇿🇦 · I. Poltoratska (5)🇩🇪 · A. Richter (5,6)🇩🇪 and 4 other authors

   The level density of 2+ states in 40Ca has been extracted in the energy region of the isoscalar giant quadrupole resonance (ISGQR) from a fluctuation analysis of high energy-resolution p,p') data taken at incident energies of 200 MeV at the K600 magnetic spectrometer of iThemba LABS, South Africa. Quasi-free scattering cross sections were calculated to estimate their role as a background contribution to the spectra and found to be small. The shape of the background was determined from the discrete wavelet transform of the spectra using a biorthogonal wavelet function normalized at the lowest particle separation threshold. The experimental results are compared to widely used phenomenological and microscopic models.

   nucl-exnucl-thPRC(2011)·16 citations
5. 05*

   Parity-violating asymmetry in $\gamma d\to \vec{n}p$ with a pionless effective theory

   J. W. Shin🇰🇷 · S.-I. Ando🇰🇷 · C. H. Hyun🇰🇷 · S. W. Hong🇰🇷

   Nuclear parity violation is studied with polarized neutrons in the photodisintegration of the deuteron at low energies. A pionless effective field theory with di-baryon fields is used for the investigation. Hadronic weak interactions are treated by parity-violating di-baryon-nucleon-nucleon vertices, which have undetermined coupling contants. A parity-violating asymmetry in the process is calculated for the incident photon energy up to 30 MeV. If experimental data for the parity-violating asymmetry become available in the future, we will be able to determine the unknown coupling contants in the parity-violating vertices.

   ↳ nucl-thnucl-exFew Body Syst.(2013)·3 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.