Wed·Nov 11, 2015Wednesday·November 11, 2015

1. 01*

   Ground and excited states of doubly open-shell nuclei from ab initio valence-space Hamiltonians

   S. R. Stroberg🇨🇦 · H. Hergert🇺🇸 · J. D. Holt🇨🇦 · S. K. Bogner🇺🇸 · A. Schwenk🇩🇪

   We present ab initio predictions for ground and excited states of doubly open-shell fluorine and neon isotopes based on chiral two- and three-nucleon interactions. We use the in-medium similarity renormalization group, in both flow-equation and Magnus formulations, to derive mass-dependent sd valence-space Hamiltonians. The experimental ground-state energies are reproduced through neutron number N=14, beyond which a new targeted normal-ordering procedure improves agreement with data and large-scale multi-reference calculations. For spectroscopy, we focus on neutron-rich 23-26F and 24-26Ne isotopes near N=14,16 magic numbers. In all cases we find an agreement with experiment competitive with established phenomenology. Moreover, yrast states are well described in 20Ne and 24Mg, providing an ab initio description of deformation in the medium-mass region.

   ↳ nucl-thnucl-exPRC(2016)·145 citations
2. 02*

   Measurement of the charged-pion polarisability at COMPASS

   Alexey Guskov (for the COMPASS collaboration)🇷🇺

   The electric (${\alpha }_{\pi }$) and the magnetic (${\beta }_{\pi }$) polarisabilities are fundamental properties of the pion characterising the rigidity of its internal structure. They have been precisely measured at the COMPASS experiment at CERN with a ${\pi }^{-}$ beam of 190~GeV/c assuming ${\alpha }_{\pi }+{\beta }_{\pi }=0$. Muons of the same momentum were used for controlling of systematic effects. The obtained result ${\alpha }_{\pi }=-{\beta }_{\pi }=(2.0\pm 0.6_{stat.}\pm 0.7_{syst.})\times 10^{-4}f{m}^3$ is in agreement with the prediction of the Chiral Perturbation Theory.

   ↳ hep-exnucl-exPoS(2015)·1 citation
3. 03*

   Sensitivity to oscillation with a sterile fourth generation neutrino from ultra-low threshold neutrino-nucleus coherent scattering

   Bhaskar Dutta · Yu Gao · Andrew Kubik · Rupak Mahapatra · Nader Mirabolfathi · Louis E. Strigari · Joel W. Walker

   We discuss prospects for probing short-range sterile neutrino oscillation using neutrino-nucleus coherent scattering with ultra-low energy ($\sim 10$ eV - 100 eV) recoil threshold cryogenic Ge detectors. The analysis is performed in the context of a specific and contemporary reactor-based experimental proposal, developed in cooperation with the Nuclear Science Center at Texas A\&M University, and references developing technology based upon economical and scalable detector arrays. The baseline of the experiment is substantially shorter than existing measurements, as near as about 2 meters from the reactor core, and is moreover variable, extending continuously up to a range of about 10 meters. This proximity and variety combine to provide extraordinary sensitivity to a wide spectrum of oscillation scales, while facilitating the tidy cancellation of leading systematic uncertainties in the reactor source and environment. With 100~eV sensitivity, for exposures on the order of 200 kg$\cdot$y, we project an estimated sensitivity to first/fourth neutrino oscillation with a mass gap $\Delta m^2\sim 1{\mathrm{eV}}^2$ at an amplitude ${\sin }^{2}2\theta \sim 10^{-1}$, or $\Delta m^2\sim 0.2{\mathrm{eV}}^2$ at unit amplitude. Larger exposures, around 5,000 kg$\cdot$y, together with 10 eV sensitivity are capable of probing more than an additional order of magnitude in amplitude.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2016)·71 citations
4. 04*

   Generator coordinate method for hypernuclear spectroscopy with a covariant density functional

   H. Mei🇯🇵 · K. Hagino🇯🇵 · J.M. Yao🇯🇵

   We apply the generator coordinate method (GCM) to single-$\Lambda$ hypernuclei in order to discuss the spectra of hypernuclear low-lying states. To this end, we use the same relativistic point-coupling energy functional both for the mean-field and the beyond-mean-field calculations. This relativistic GCM approach provides a unified description of low-lying states in ordinary nuclei and in hypernuclei, and is thus suitable for studying the $\Lambda$ impurity effect. We carry out an illustrative calculation for the low-lying spectrum of ${}_{\Lambda }^{21}$Ne, in which the interplay between the hypernuclear collective excitations and the single-particle excitations of the unpaired $\Lambda$ hyperon is taken into account in a full microscopic manner.

   ↳ nucl-thnucl-exPRC(2016)·27 citations
5. 05*

   Will protons become gray at 13 TeV and 100 TeV?

   I.M. Dremin🇷🇺

   It is shown that the regime of pp-interactions at 7 TeV is a critical one. The LHC data about elastic pp-scattering at 7 and 8 TeV are used to get some information about both elastic and inelastic profiles of pp-collisions. They are discussed in the context of two phenomenological models which pretend to describe the high energy pp-data with high accuracy. Some predictions following from these models for LHC energy 13 TeV and for energy 95 TeV of the newly proposed collider are discussed. It is claimed that the center of the inelastic interaction region will become less dark with increase of energy albeit very slowly.

   ↳ hep-phhep-exnucl-exnucl-thBull.Lebedev Phys.Inst.(2017)·9 citations
6. 06*

   Di-hadron fragmentation and mapping of the nucleon structure

   Silvia Pisano🇮🇹 · Marco Radici🇮🇹

   The fragmentation of a colored parton directly into a pair of colorless hadrons is a non-perturbative mechanism that offers important insights into the nucleon structure. Di-hadron fragmentation functions can be extracted from semi-inclusive electron-positron annihilation data. They also appear in observables describing the semi-inclusive production of two hadrons in deep-inelastic scattering of leptons off nucleons or in hadron-hadron collisions. When a target nucleon is transversely polarized, a specific chiral-odd di-hadron fragmentation function can be used as the analyzer of the net density of transversely polarized quarks in a transversely polarized nucleon, the so-called transversity distribution. The latter can be extracted through suitable single-spin asymmetries in the framework of collinear factorization, thus in a much simpler framework with respect to the traditional one in single-hadron fragmentation. At subleading twist, the same chiral-odd di-hadron fragmentation function provides the cleanest access to the poorly known twist-3 parton distribution $e(x)$, which is intimately related to the mechanism of dynamical chiral symmetry breaking in QCD. When sensitive to details of transverse momentum dynamics of partons, the di-hadron fragmentation functions for a longitudinally polarized quark can be connected to the longitudinal jet handedness to explore possible effects due to $CP-$violation of the QCD vacuum. In this review, we outline the formalism of di-hadron fragmentation functions, we discuss different observables where they appear and we present measurements and future worldwide plans.

   ↳ hep-phhep-exnucl-exnucl-thEPJA(2016)·21 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.