Fri·Dec 22, 2017Friday·December 22, 2017

1. 01*

   Relative particle yield fluctuations in Pb-Pb collisions at $\sqrt{{\mathbf{s}}_{\mathrm{NN}}}=2.76$ TeV

   ALICE Collaboration

   First results on K/$\pi$, p/$\pi$ and K/p fluctuations are obtained with the ALICE detector at the CERN LHC as a function of centrality in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV. The observable ${\nu }_{\mathrm{dyn}}$, which is defined in terms of the moments of particle multiplicity distributions, is used to quantify the magnitude of dynamical fluctuations of relative particle yields and also provides insight into the correlation between particle pairs. This study is based on a novel experimental technique, called the Identity Method, which allows one to measure the moments of multiplicity distributions in case of incomplete particle identification. The results for p/$\pi$ show a change of sign in ${\nu }_{\mathrm{dyn}}$ from positive to negative towards more peripheral collisions. For central collisions, the results follow the smooth trend of the data at lower energies and ${\nu }_{\mathrm{dyn}}$ exhibits a change in sign for p/$\pi$ and K/p.

   nucl-exhep-exEPJC(2019)·27 citations
2. 02*

   Centrality determination of Au+Au collisions at 1.23A GeV with HADES

   HADES collaboration: J. Adamczewski-Musch · O. Arnold · C. Behnke · A. Belounnas · A. Belyaev · S. Chernenko · L. Chlad · C. Deveaux · J. Dreyer · A. Dybczak · E. Epple · L. Fabbietti and 96 other authors

   The centrality determination for Au+Au collisions at 1.23A GeV, as measured with HADES at the GSI-SIS18, is described. In order to extract collision geometry related quantities, such as the average impact parameter or number of participating nucleons, a Glauber Monte Carlo approach is employed. For the application of this model to collisions at this relatively low centre-of-mass energy of $\sqrt{s_{\mathrm{NN}}}=2.42$ GeV special investigations were performed. As a result a well defined procedure to determine centrality classes for ongoing analyses of heavy-ion data is established.

   nucl-exEPJA(2018)·80 citations
3. 03*

   The CUORE experiment at LNGS

   Davide Chiesa (on behalf of the CUORE collaboration)🇮🇹

   The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. The construction of the experiment and, in particular, the installation of all towers in the cryostat was completed in August 2016, followed by the cooldown to base temperature at the beginning of 2017. The CUORE detector is now operational and has been taking science data since Spring 2017. We present here the initial performance of the detector and the preliminary results from the first detector run.

   nucl-exphysics.ins-det2 citations
4. 04*

   Generalisation of the identity method for determination of high-order moments of multiplicity distributions with a software implementation

   Maja Mackowiak-Pawlowska🇵🇱 · Piotr Przybyla🇬🇧

   The incomplete particle identification limits the experimentally-available phase space region for identified particle analysis. This problem affects ongoing fluctuation and correlation studies including the search for the critical point of strongly interacting matter performed on SPS and RHIC accelerators. In this paper we provide a procedure to obtain $n$-th order moments of the multiplicity distribution using the identity method, generalising previously published solutions for $n=2$ and $n=3$. Moreover, we present an open source software implementation of this computation, called \textit{Idhim}, that allows one to obtain the true moments of identified particle multiplicity distributions from the measured ones provided the response function of the detector is known.

   ↳ hep-exhep-phnucl-exEPJC(2018)·3 citations
5. 05*

   Modification of $\Delta (1232)$ in the neutrino nucleus reaction

   Swapan Das🇮🇳

   The remarkable observations in the pion induced and charge exchange reactions on a nucleus are the significant shift and broadening of the $\Delta (1232)$-peak relative to free pion nucleon scattering. For the forward going massless leptons, the weak process $({\nu }_l,l)$ on a nucleon, according to Adler's partially conserved axial current theorem, is connected to the pion nucleon scattering. This mechanism is also applicable to the nucleus. Therefore, the modification of the $\Delta$-peak in a nucleus can be seen in the $({\nu }_l,l)$ reaction since it is connected to the pion nucleus scattering. To investigate this issue quantitatively, the double differential cross sections of the forward going ejectile $l$ energy distribution in the $({\nu }_l,l)$ reaction are calculated in the $\Delta$-excitation region for both proton and nucleus. The measured pion nucleon and pion nucleus scattering cross sections in the quoted energy region are used in these reactions as input. Since the $({\nu }_l,l)$ reaction is connected to the pion induced scattering, the features of the previous reaction is shown analogous to those of the later.

   ↳ nucl-thnucl-exActa Phys.Polon.B(2017)·0 citations
6. 06*

   Shadowing in the low energy photonuclear reaction

   Swapan Das🇮🇳

   The photonuclear reaction in the multi-GeV region occurs because of the electromagnetic and hadronic interaction. The later originates due to the hadronic fluctuation, i.e., vector meson, of the photon. The total cross section of the reaction is shadowed because of the vector meson nucleus (hadronic) interaction. To estimate it quantitatively, the cross section of the photonuclear reaction was calculated in the low energy region ($\sim 1-3$ GeV) using simple vector meson dominance (SVMD) model, i.e., the low lying vector mesons (${\rho }^0$, $\omega$ and $\varphi$ mesons) were considered. The nuclear shadowing is reinvestigated using generalized vector meson (GVMD) model, where the higher $\rho$ meson effective state (${\rho }^{\prime }$ meson) is taken into account along with the low lying vector mesons. Using GVMD model, the shadowing and the total cross section of the photonuclear reaction are calculated in the above mentioned energy region. The calculated results have been compared with the measured spectra.

   ↳ nucl-thnucl-exPRC(2017)·3 citations
7. 07*

   A Review and Outlook for the Removal of Radon-Generated Po-210 Surface Contamination

   V.E. Guiseppe · C.D. Christofferson · K.R. Hair · F.M. Adams

   The next generation low-background detectors operating deep underground aim for unprecedented low levels of radioactive backgrounds. The deposition and presence of radon progeny on detector surfaces is an added source of energetic background events. In addition to limiting the detector material's radon exposure in order to reduce potential surface backgrounds, it is just as important to clean surfaces to remove inevitable contamination. Such studies of radon progeny removal have generally found that a form of etching is effective at removing some of the progeny (Bi and Pb), however more aggressive techniques, including electropolishing, have been shown to effectively remove the Po atoms. In the absence of an aggressive etch, a significant fraction of the Po atoms are believed to either remain behind within the surface or redeposit from the etching solution back onto the surface. We explore the chemical nature of the aqueous Po ions and the effect of the oxidation state of Po to maximize the Po ions remaining in the etching solution of contaminated Cu surfaces. We present a review of the previous studies of surface radon progeny removal and our findings on the role of oxidizing agents and a cell potential in the preparation of a clean etching technique.

   ↳ physics.ins-detnucl-exAIP Conf.Proc.(2018)·9 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.