Tue·Feb 3, 2015Tuesday·February 3, 2015

1. 01*

   Direct probes of neutrino mass

   R. G. Hamish Robertson🇺🇸

   The discovery of neutrino oscillations has shown that neutrinos, in contradiction to a prediction of the minimal standard model, have mass. Oscillations do not yield a value for the mass, but do set a lower limit of 0.02 eV on the average of the 3 known eigenmasses. Moreover, they make it possible to determine or limit all 3 masses from measurements of electron-flavor neutrinos in beta decay. The present upper limit from such measurements is 2 eV. We review the status of laboratory work toward closing the remaining window between 2 and 0.02 eV, and measuring the mass.

   nucl-exhep-exphysics.ins-detNucl.Part.Phys.Proc.(2015)·5 citations
2. 02*

   Forward-backward multiplicity correlations in pp collisions at $\sqrt{s}$=0.9, 2.76 and 7 TeV

   ALICE Collaboration

   The strength of forward-backward (FB) multiplicity correlations is measured by the ALICE detector in proton-proton (pp) collisions at $\sqrt{s}=0.9$, 2.76 and 7 TeV. The measurement is performed in the central pseudorapidity region ($|\eta |<0.8$) for the transverse momentum $p_{\mathrm{T}}>0.3$ GeV/$c$. Two separate pseudorapidity windows of width ($\delta \eta$) ranging from 0.2 to 0.8 are chosen symmetrically around $\eta =0$. The multiplicity correlation strength ($b_{\mathrm{cor}}$) is studied as a function of the pseudorapidity gap (${\eta }_{\mathrm{gap}}$) between the two windows as well as the width of these windows. The correlation strength is found to decrease with increasing ${\eta }_{\mathrm{gap}}$ and shows a non-linear increase with $\delta \eta$. A sizable increase of the correlation strength with the collision energy, which cannot be explained exclusively by the increase of the mean multiplicity inside the windows, is observed. The correlation coefficient is also measured for multiplicities in different configurations of two azimuthal sectors selected within the symmetric FB $\eta$-windows. Two different contributions, the short-range (SR) and the long-range (LR), are observed. The energy dependence of $b_{\mathrm{cor}}$ is found to be weak for the SR component while it is strong for the LR component. Moreover, the correlation coefficient is studied for particles belonging to various transverse momentum intervals chosen to have the same mean multiplicity. Both SR and LR contributions to $b_{\mathrm{cor}}$ are found to increase with $p_{\mathrm{T}}$ in this case. Results are compared to PYTHIA and PHOJET event generators and to a string-based phenomenological model. The observed dependencies of $b_{\mathrm{cor}}$ add new constraints on phenomenological models.

   nucl-exJHEP(2015)·62 citations
3. 03*

   Evaluation of Stopping Powers of Superheavy Ions with $Z$ up to 124 in Al and U

   Yong Hee Chung

   Electronic and nuclear stopping powers of superheavy ions with $Z$ up to 124 and $A$=300 in Al and U were estimated in the energy range of 0.01-0.20 MeV/u. The corresponding stopping powers were estimated using stopping powers of ions with 6$\le$$Z$$\le$92 obtained from SRIM. The results were compared with those deduced from Northcliffe and Schilling${}^{\prime }$s stopping-power tables and with experimental data for ${}^{16}$O and ${}^{19}$F ions in Al. Estimated electronic stopping powers of the light ions agreed better with their experimental values above 0.10 MeV/u than the SRIM data.

   nucl-exJ.Korean Phys.Soc.(2015)·0 citations
4. 04*

   Luminosity determination for the deutron-deutron reactions using free and quasi-free reactions with WASA-at-COSY detector

   M. Skurzok🇵🇱 · P. Moskal🇵🇱 · W. Krzemien🇵🇱

   Two methods of the luminosity determination for the experiment performed by WASA collaboration to search for ${}^4-0.03cmHe$-$\eta$ bound state are presented. During the measurement the technique of continous change of the beam momentum in one accelerator cycle (called ramped beam) was applied. This imposes the requirement to determine not only the total integrated luminosity, but also its variation as a function of the beam momentum.

   nucl-exActa Phys.Polon.B(2015)·6 citations
5. 05*

   Event-by-event mean p_T fluctuations in pp and Pb-Pb collisions at the LHC

   S. T. Heckel (for the ALICE Collaboration)🇩🇪

   The ALICE detector at the LHC is used to study the properties of the Quark-Gluon Plasma produced in heavy-ion collisions. As a reference measurement, also the analysis of proton-proton (pp) collisions is very important. In the study presented here, event-by-event fluctuations of the mean transverse momentum are analysed in pp collisions at sqrt(s) = 0.9, 2.76 and 7 TeV, and Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV as a function of the charged-particle multiplicity. In both systems, dynamical fluctuations beyond the statistical expectation are observed. In pp collisions, no significant dependence on collision energy is found, even in comparison to inclusive results at much lower collision energies. Likewise, central A-A collisions show only little dependence on collision energy. The multiplicity dependence observed in peripheral Pb-Pb data is in agreement with that in pp collisions. Going to more central Pb-Pb collisions, a clear deviation from this trend is found, reaching a significant reduction of the fluctuations in most central collisions. Comparisons to Monte Carlo event generators show good agreement in pp, but rather large differences in Pb-Pb collisions.

   nucl-exhep-exhep-phnucl-thEPJ Web Conf.(2015)·9 citations
6. 06*

   Two-pion femtoscopy in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   We report the results of the femtoscopic analysis of pairs of identical pions measured in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. Femtoscopic radii are determined as a function of event multiplicity and pair momentum in three spatial dimensions. As in the pp collision system, the analysis is complicated by the presence of sizable background correlation structures in addition to the femtoscopic signal. The radii increase with event multiplicity and decrease with pair transverse momentum. When taken at comparable multiplicity, the radii measured in p-Pb collisions, at high multiplicity and low pair transverse momentum, are 10-20% higher than those observed in pp collisions but below those observed in A-A collisions. The results are compared to hydrodynamic predictions at large event multiplicity as well as discussed in the context of calculations based on gluon saturation.

   nucl-exPRC(2015)·109 citations
7. 07*

   Tunneling of atoms, nuclei and molecules

   C.A. Bertulani🇺🇸

   This is a brief review of few relevant topics on tunneling of composite particles and how the coupling to intrinsic and external degrees of freedom affects tunneling probabilities. I discuss the phenomena of resonant tunneling, different barriers seen by subsystems, damping of resonant tunneling by level bunching and continuum effects due to particle dissociation.

   ↳ nucl-thcond-mat.supr-connucl-exquant-phFew Body Syst.(2015)·6 citations
8. 08*

   Quantifying properties of hot and dense QCD matter through systematic model-to-data comparison

   Jonah E. Bernhard🇺🇸 · Peter W. Marcy🇺🇸 · Christopher E. Coleman-Smith🇺🇸 · Snehalata Huzurbazar🇺🇸 · Robert L. Wolpert🇺🇸 · Steffen A. Bass🇺🇸

   We systematically compare an event-by-event heavy-ion collision model to data from the Large Hadron Collider. Using a general Bayesian method, we probe multiple model parameters including fundamental quark-gluon plasma properties such as the specific shear viscosity $\eta /s$, calibrate the model to optimally reproduce experimental data, and extract quantitative constraints for all parameters simultaneously. The method is universal and easily extensible to other data and collision models.

   ↳ nucl-thhep-phnucl-exPRC(2015)·112 citations
9. 09*

   Determination of the polarization in the $\vec{p}p\to pp$ reaction with WASA-at-COSY detector

   I. Schatti-Ozerianska🇵🇱 · P. Moskal🇵🇱 · M. Zielinski🇵🇱

   The dynamics of $\eta$-meson production and the interaction of $\eta$-mesons with nucleons can be studied using the $\vec{p}p\to pp\eta$ reaction via measurements of the analyzing power $A_y$. To this end, we have performed a measurement of the $\vec{p}p\to pp\eta$ reaction using the WASA-at-COSY detector, which provides large acceptance and is $\phi$-symmetric. The experiment was carried out for beam momenta of $2026$ MeV/c and $2188$ MeV/c. In this article we present a method and results for the determination of the degree of the beam polarization.

   ↳ hep-exnucl-exActa Phys.Polon.B(2015)·4 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.