Tue·Oct 13, 2015Tuesday·October 13, 2015

1. 01*

   Intermediate Mass Fragment Emission in ${}^{32}$S +${}^{51}$V, ${}^{109}$Ag, and ${}^{238}$U Collisions at E~=~31.6~MeV~A

   H. Machner🇩🇪 · M. Nolte · M. Palarczyk · T. Kutsarova🇧🇬

   Intermediate mass fragment emission for reactions of ${}^{32}\text{S}+{}^{51}\text{V},{}^{109}$Ag, and ${}^{238}\text{U}$ has been studied. Double differential cross sections were analysed in terms of the generalised moving source model yielding charge distributions. Isotope ratios show strong fragment mass dependencies. The data were successfully reproduced by the coalescence model as well as by statistical multifragmentation model calculations. Quantum molecular dynamics model calculations were not so successful.

   nucl-exnucl-thEPJA(2015)·1 citation
2. 02*

   No influence of a N=126 Neutron Shell Closure in Fission Fragment Mass Distributions

   A. Chaudhuri🇮🇳 · T. K. Ghosh🇮🇳 · K. Banerjee🇮🇳 · S. Bhattacharya🇮🇳 · Jhilam Sadhukhan🇮🇳 · S. Kundu🇮🇳 · C. Bhattacharya🇮🇳 · J. K. Meena · G. Mukherjee🇮🇳 · A. K. Saha🇮🇳 · Md. A. Asgar🇮🇳 · A. Dey🇮🇳 and 15 other authors

   Mass distributions of the fragments in the fission of ${}^{206}$Po and the N=126 neutron shell closed nucleus ${}^{210}$Po have been measured. No significant deviation of mass distributions has been found between ${}^{206}$Po and ${}^{210}$Po, indicating the absence of shell correction at the saddle point in both the nuclei, contrary to the reported angular anisotropy and pre-scission neutron multiplicity results. This new result provides benchmark data to test the new fission dynamical models to study the effect of shell correction on the potential energy surface at saddle point.

   nucl-exnucl-thPRC(2015)·18 citations
3. 03*

   Measurement of long-range near-side two-particle angular correlations in pp collisions at sqrt(s) = 13 TeV

   CMS Collaboration

   Results on two-particle angular correlations for charged particles produced in pp collisions at a center-of-mass energy of 13 TeV are presented. The data were taken with the CMS detector at the LHC and correspond to an integrated luminosity of about 270 inverse nanobarns. The correlations are studied over a broad range of pseudorapidity (abs(eta) < 2.4) and over the full azimuth (phi) as a function of charged particle multiplicity and transverse momentum (pt). In high-multiplicity events, a long-range (abs(Delta eta) > 2.0), near-side (Delta phi approximately 0) structure emerges in the two-particle Delta eta-Delta phi correlation functions. The magnitude of the correlation exhibits a pronounced maximum in the range 1.0 < pt < 2.0 GeV/c and an approximately linear increase with the charged particle multiplicity, with an overall correlation strength similar to that found in earlier pp data at sqrt(s) = 7 TeV. The present measurement extends the study of near-side long-range correlations up to charged particle multiplicities of N[ch] approximately 180, a region so far unexplored in pp collisions. The observed long-range correlations are compared to those seen in pp, pPb, and PbPb collisions at lower collision energies.

   nucl-exhep-exPRL(2016)·326 citations
4. 04*

   A study of event-by-event fluctuations in relativistic heavy-ion collisions

   Shakeel Ahmad🇮🇳 · M.M. Khan🇮🇳 · Shaista Khan🇮🇳 · A. Khatun🇮🇳 · M. Irfan🇮🇳

   A method for selecting events with densely populated narrow regions or spikes in a given data sample is discussed. Applying this method to 200 A GeV/c 32S-AgBr and 32S-Gold collision data, a few events having "hot regions" are chosen for further analysis. The finding reveals that a systematic study of particle density fluctuations, if carried out in terms of scaled factorial moments, and the results are compared with those for the analysis of correlation free Monte Carlo events, would be useful in identifying events with large dynamical fluctuations. Formation of clusters or jet-like structure in multihadronic final states in the selected spiky events is also looked into and compared with the predictions of AMPT and independent emission hypothesis models by carrying out Monte Carlo simulation. The findings suggest that clustering or jet-like algorithm adopted in the present study may also serve as an important tool for triggering different classes of events.

   nucl-exIJMPE(2014)·12 citations
5. 05*

   Transverse momentum spectra of b jets in pPb collisions at sqrt(s[NN]) = 5.02 TeV

   CMS Collaboration

   We present a measurement of b jet transverse momentum (pt) spectra in proton-lead (pPb) collisions using a dataset corresponding to about 35 inverse nanobarns collected with the CMS detector at the LHC. Jets from b quark fragmentation are found by exploiting the long lifetime of hadrons containing a b quark through tagging methods using distributions of the secondary vertex mass and displacement. Extracted cross sections for b jets are scaled by the effective number of nucleon-nucleon collisions and are compared to a reference obtained from PYTHIA simulations of pp collisions. The PYTHIA-based estimate of the nuclear modification factor is found to be 1.22 +/- 0.15 (stat + syst pPb) +/- 0.27 (syst PYTHIA) averaged over all jets with pt between 55 and 400 GeV/c and with abs(eta[lab]) < 2. We also compare this result to predictions from models using perturbative calculations in quantum chromodynamics.

   nucl-exhep-exPLB(2016)·70 citations
6. 06*

   Structure of the neutral pion and its electromagnetic transition form factor

   K. Raya🇲🇽 · L. Chang🇨🇳 · A. Bashir🇲🇽 · J. J. Cobos-Martinez🇲🇽 · L. X. Gutiérrez-Guerrero🇲🇽 · C. D. Roberts🇺🇸 · P. C. Tandy🇺🇸

   The ${\gamma }^{\ast }\gamma \to {\pi }^0$ transition form factor, $G(Q^2)$, is computed on the entire domain of spacelike momenta using a continuum approach to the two valence-body bound-state problem in relativistic quantum field theory: the result agrees with data obtained by the CELLO, CLEO and Belle Collaborations. The analysis unifies this prediction with that of the pion's valence-quark parton distribution amplitude (PDA) and elastic electromagnetic form factor, and demonstrates, too, that a fully self-consistent treatment can readily connect a pion PDA that is a broad, concave function at the hadronic scale with the perturbative QCD prediction for the transition form factor in the hard photon limit. The normalisation of that limit is set by the scale of dynamical chiral symmetry breaking, which is a crucial feature of the Standard Model. Understanding of the latter will thus remain incomplete until definitive transition form factor data is available on $Q^2>10$GeV${}^2$.

   ↳ nucl-thhep-exhep-lathep-ph+1PRD(2016)·131 citations
7. 07*

   Big Bang Nucleosynthesis and the Helium Isotope Ratio

   Ryan Cooke (University of California, Santa Cruz)🇺🇸

   The conventional approach to search for departures from the standard model of physics during Big Bang Nucleosynthesis involves a careful, and subtle measurement of the mass fraction of baryons consisting of helium. Recent measurements of this quantity tentatively support new physics beyond the standard model but, historically, this method has suffered from hidden systematic uncertainties. In this letter, I show that a combined measurement of the primordial deuterium abundance and the primordial helium isotope ratio has the potential to provide a complementary and reliable probe of new physics beyond the standard model. Using the recent determination of the primordial deuterium abundance and assuming that the measured pre-solar 3He/4He meteoritic abundance reflects the primordial value, a bound can be placed on the effective number of neutrino species, Neff(BBN) = 3.01 (+0.95 -0.76, with 95 per cent confidence). Although this value of Neff supports the standard model, it is presently unclear if the pre-solar 3He/4He ratio reflects the primordial value. New astrophysical measurements of the helium isotope ratio in near-pristine environments, together with updated calculations and experimental values of several important nuclear reactions (some of which are already being attempted), will lead to much improved limits on possible departures from the standard model. To this end, I describe an analysis strategy to measure the 3He I flux emitted from nearby low metallicity H II regions. The proposed technique can be attempted with the next generation of large telescopes, and will be easier to realize in metal-poor H II regions with quiescent kinematics.

   ↳ astro-ph.COnucl-exApJL(2015)·18 citations
8. 08*

   Realistic estimate of valence transversity from dihadron production

   Marco Radici🇮🇹

   We have updated our extraction of the transversity parton distribution based on the analysis of pion-pair production in deep-inelastic scattering off transversely polarized targets in collinear factorization. The most recent COMPASS data for proton and deuteron targets, complemented by previous HERMES data on the proton, make it possible to perform a flavor separation of the valence components of the transversity distribution, using di-hadron fragmentation functions taken from the semi-inclusive production of two pion pairs in back-to-back jets in $e^{+}{e}^{-}$ annihilation. The $e^{+}{e}^{-}$ data from BELLE have been reanalyzed to reach a more realistic estimate of the uncertainties on the chiral-odd interference fragmentation function. Our results represent the most accurate estimate of the uncertainties on the valence components of the transversity distribution currently available.

   ↳ hep-phhep-exnucl-exnucl-th0 citations
9. 09*

   Multiplicity fluctuations in heavy-ion collisions using canonical and grand-canonical ensemble

   P. Garg🇮🇳 · D. K. Mishra🇮🇳 · P. K. Netrakanti🇮🇳 · A. K. Mohanty🇮🇳

   We report the higher order cumulants and their ratios for baryon, charge and strangeness multiplicity in canonical and grand-canonical ensembles in ideal thermal model including all the resonances. When the number of conserved quanta is small, an explicit treatment of these conserved charges is required, which leads to a canonical description of the system and the fluctuations are significantly different from the grand canonical ensemble. Cumulant ratios of total charge and net-charge multiplicity as a function of collision energies are also compared in grand canonical ensemble.

   ↳ nucl-thhep-phnucl-exEPJA(2016)·3 citations
10. 10*

    The long and winding road from chiral effective Lagrangians to nuclear structure

    Ulf-G Meißner🇩🇪

    I review the chiral dynamics of nuclear physics. In the first part, I discuss the new developments in the construction of the forces between two, three and four nucleons which have been partly carried out to fifth order in the chiral expansion. It is also shown that based on these forces in conjunction with the estimation of the corresponding theoretical uncertainties, the need for three-nucleon forces in few nucleon systems can be unambiguously established. I also introduce the lattice formulation of these forces, which allow for truly ab initio calculations of nuclear structure and reactions. I present some pertinent results of the nuclear lattice approach. Finally, I discuss how few-nucleon systems and nuclei can be used to explore symmetries and physics within and beyond the Standard Model.

    ↳ nucl-thhep-lathep-phnucl-exPhys.Scripta(2016)·37 citations
11. 11*

    Isospin effects in N~Z nuclei in extended Density Functional Theory

    Wojciech Satula🇵🇱 · Witold Nazarewicz🇺🇸

    This paper overviews various phenomena related to the concept of isospin symmetry. The focus is on N~Z nuclei, which are excellent laboratories of isospin physics. The theoretical framework applied is nuclear Density Functional Theory and its isospin- and angular-momentum projected extensions, as well as symmetry-projected multi-reference models. The topics covered include: isospin impurities, superallowed beta decays, beta-transitions in mirror nuclei, isospin breaking hadronic interactions, mirror and triplet binding energy differences, and isoscalar pairing.

    ↳ nucl-thnucl-exPhys.Scripta(2016)·15 citations
12. 12*

    NuWro Monte Carlo generator of neutrino interactions - first electron scattering results

    Jakub Zmuda🇵🇱 · Krzysztof M. Graczyk🇵🇱 · Cezary Juszczak🇵🇱 · Jan T. Sobczyk🇵🇱

    NuWro Monte Carlo generator of events is presented. It is a numerical environment containing all necessary ingredients to simulate interactions of neutrinos with nucleons and nuclei in realistic experimental situation in wide neutrino energy range. It can be used both for data analysis as well as studies of nuclear effects in neutrino interactions. The first results and functionalities of eWro - module of NuWro dedicated to electron nucleus scattering - are also presented.

    ↳ hep-phnucl-exnucl-thActa Phys.Polon.B(2015)·30 citations
13. 13*

    Evidence for the virtual beta-gamma transition in 59Ni

    M. Pfützner🇬🇧 · K. Pachucki🇵🇱 · J. Żylicz

    A novel theory of radiative electron capture in second forbidden non-unique transition, is applied to reanalyze experimental data obtained previously for the decay of 59Ni. The measured gamma spectrum is shown to be distorted at the high-energy end, presenting the first direct evidence for the virtual beta-gamma transition through the excited state in 59Co. The complete theoretical predictions, including both the direct and the virtual decay channels, as well as the interference between them, reproduce very well the experimental spectrum. The virtual nuclear component amounts to about 4% of the total gamma intensity.

    ↳ nucl-thnucl-exPRC(2015)·5 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.