Wed·Aug 5, 2009Wednesday·August 5, 2009

1. 01*

   The low-temperature energy calibration system for the CUORE bolometer array

   S. Sangiorgio🇺🇸 · L. M. Ejzak🇺🇸 · K. M. Heeger🇺🇸 · R. H. Maruyama🇺🇸 · A. Nucciotti🇮🇹 · M. Olcese🇮🇹 · T. S. Wise🇺🇸 · A. L. Woodcraft🇬🇧

   The CUORE experiment will search for neutrinoless double beta decay (0nDBD) of 130Te using an array of 988 TeO_2 bolometers operated at 10 mK in the Laboratori Nazionali del Gran Sasso (Italy). The detector is housed in a large cryogen-free cryostat cooled by pulse tubes and a high-power dilution refrigerator. The TeO_2 bolometers measure the event energies, and a precise and reliable energy calibration is critical for the successful identification of candidate 0nDBD and background events. The detector calibration system under development is based on the insertion of 12 gamma-sources that are able to move under their own weight through a set of guide tubes that route them from deployment boxes on the 300K flange down into position in the detector region inside the cryostat. The CUORE experiment poses stringent requirements on the maximum heat load on the cryostat, material radiopurity, contamination risk and the ability to fully retract the sources during normal data taking. Together with the integration into a unique cryostat, this requires careful design and unconventional solutions. We present the design, challenges, and expected performance of this low-temperature energy calibration system.

   nucl-exAIP Conf.Proc.(2009)·3 citations
2. 02*

   The centrality dependence of v2/epsilon: the ideal hydro limit and eta/s

   H. Masui · J-Y. Ollitrault🇫🇷 · R. Snellings · A. Tang

   The large elliptic flow observed at RHIC is considered to be evidence for almost perfect liquid behavior of the strongly coupled quark-gluon plasma produced in the collisions. In these proceedings we present a two parameter fit for the centrality dependence of the elliptic flow scaled by the spatial eccentricity. We show by comparing to viscous hydrodynamical calculations that these two parameters are in good approximation proportional to the shear viscosity over entropy ratio and the ideal hydro limit of the ratio v2/epsilon.

   nucl-exNPA(2009)·21 citations
3. 03*

   Heavy-quark azimuthal momentum correlations as a sensitive probe of thermalization

   G. Tsiledakis🇩🇪 · H. Appelshaeuser🇩🇪 · K. Schweda🇩🇪 · J. Stachel🇩🇪

   In high-energy nuclear collisions the degree of thermalization at the partonic level is a key issue. Due to their large mass, heavy quarks and their possible participation in the collective flow of the QCD-medium constitute a powerful probe for thermalization. We present studies with PYTHIA for p+p collisions at the top LHC energy of $\sqrt{s}$ = 14 TeV applying the two-particle transverse momentum correlator $<\Delta p_{t,1},\Delta p_{t,2}>$ to pairs of heavy-quark hadrons and their semi-leptonic decay products as a function of their relative azimuth. Modifications or even the complete absence of initially existing correlations in Pb+Pb collisions might indicate thermalization at the partonic level.

   nucl-exNPA(2011)·6 citations
4. 04*

   Chern-Simons current and local parity violation in hot QCD matter

   Dmitri E. Kharzeev🇺🇸

   Non-Abelian gauge theories "live" in a space-time with non-trivial topology that can be characterized by an odd-dimensional Chern-Simons form. In QCD, Chern-Simons form is induced by the chiral anomaly and the presence of topological solutions; it opens a possibility for the breaking of P and CP invariances in strong interactions ("the strong CP problem"). While there is apparently no global P and CP violation in QCD, here I argue that topological fluctuations in hot quark-gluon matter can become directly observable in the presence of a very intense external magnetic field by inducing local P- and CP- odd effects. These phenomena can be described by using the Maxwell-Chern-Simons electrodynamics as an effective theory. Local P and CP violation in hot QCD matter can be observed in experiment through the "chiral magnetic effect" - the separation of electric charge along the axis of magnetic field that is created by the colliding relativistic ions. There is a recent evidence for the electric charge separation relative to the reaction plane of heavy ion collisions from the STAR Collaboration at RHIC.

   ↳ hep-phnucl-exnucl-thNPA(2009)·54 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.