Mon·Feb 8, 2016Monday·February 8, 2016

1. 01*

   The quest for an electric dipole moment of the neutron

   P. Schmidt-Wellenburg🇨🇭

   Until this day no electric dipole moment of the neutron (nEDM) has been observed. Why it is so vanishing small, escaping detection in the last 50 years, is not easy to explain. In general it is considered as the most sensitive probe for the violation of the combined symmetry of charge and parity (CP). A discovery could shed light on the poorly understood matter/anti-matter asymmetry of the universe. As nucleon it might one day help to distinguish different sources of CP-violation in combination with measurements of the electron and diamagnetic EDMs. This proceedings articles presents an overview of the most important concepts in searches for an nEDM and presents a brief overview of the world wide efforts.

   nucl-exhep-exhep-phphysics.ins-detAIP Conf.Proc.(2016)·20 citations
2. 02*

   Reply to "Comment on `Breakdown of the expansion of finite-size corrections to the hydrogen Lamb shift in moments of charge distribution'"

   Franziska Hagelstein🇩🇪 · Vladimir Pascalutsa (KPH, JGU Mainz)🇩🇪

   To comply with the critique of the Comment [J. Arrington, arXiv:1602.01461], we consider another modification of the proton electric form factor, which resolves the "proton-radius puzzle". The proposed modification satisfies all the consistency criteria put forward in the Comment, and yet has a similar impact on the puzzle as that of the original paper. Contrary to the concluding statement of the Comment, it is not difficult to find an ad hoc modification of the form factor at low $Q$ that resolves the discrepancy and is consistent with analyticity constraints. We emphasize once again that we do not consider such an ad hoc modification of the proton form factor to be a solution of the puzzle until a physical mechanism for it is found.

   ↳ hep-phnucl-exnucl-thphysics.atom-phPRA(2016)·2 citations
3. 03*

   High order flow harmonics of identified hadrons in 2.76 A TeV Pb+Pb collisions

   Hao-jie Xu🇨🇳 · Zhuopeng Li🇨🇳 · Huichao Song🇨🇳

   Using iEBE-VISHNU hybrid model with the AMPT initial conditions, we study the higher order flow harmonics of identified hadrons in 2.76 A TeV Pb+Pb collisions. Comparison with the recent ALICE measurements at 20-30\% centrality shows that our calculations nicely describe the data below 2 GeV, especially for the $v_2$, $v_3$ and $v_4$ mass-orderings among pions, kaons and protons. We also extended the calculations to other centrality bins, which presents similar mass-ordering patterns for these flow harmonics as the ones observed at 20-30\% centrality. In the later part of this article, we explore the development of $v_n$ mass ordering/splitting during the hadronic evolution through the comparison runs from iEBE-VISHNU hybrid model and pure hydrodynamics with different decoupling temperatures.

   ↳ nucl-thhep-phnucl-exPRC(2016)·60 citations
4. 04*

   Transport Coefficient to Trace Anomaly in the Clustering of Color Sources Approach

   J. Dias de Deus🇵🇹 · A. S. Hirsch🇺🇸 · C. Pajares🇪🇸 · R. P. Scharenberg🇺🇸 · B. K. Srivastava🇺🇸

   From our previously obtained shear viscosity to entropy density ratio ($\eta /s$) in the framework of clustering of color sources (Color String Percolation Model: CSPM), we calculate the jet quenching parameter $\hat{q}$ and trace anomaly $\Delta =(\epsilon -3p)/T^4$ as a function of temperature. It is shown that the scaled $\hat{q}/T^3$ is in agreement with the recent JET Collaboration estimates. The inverse of $\eta /s$ is found to represent $\Delta$. The results for $\Delta$ are in excellent agreement with Lattice Quantum Chromo Dynamics (LQCD) simulations. From the trace anomaly and energy density $ϵ$, the equation of state is obtained as a function of temperature and compared with LQCD simulations. It is possible that there is a direct connection between the $\eta /s$ and $\Delta$. Thus the estimate of transport coefficient $\eta /s$ provides $\hat{q}$ and $\Delta$ as a function of temperature. Both $\Delta$ and $\eta /s$ describe the transition from a strongly coupled QGP to a weakly coupled QGP.

   ↳ nucl-thhep-lathep-phnucl-exPRC(2016)·16 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.