tag:blogger.com,1999:blog-10827760181067269552024-02-08T11:30:11.382-08:00Nuclear ExperimentSite for <a href="http://communitypeerreview.blogspot.com/">Community Peer Review</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.comBlogger2122125tag:blogger.com,1999:blog-1082776018106726955.post-30286326090296843302013-08-06T00:04:00.001-07:002013-08-06T00:04:00.165-07:001308.0617 (Shanshan Cao et al.)<h2 class="title"><a href="http://arxiv.org/abs/1308.0617">Heavy quark dynamics and hadronization in ultra-relativistic heavy-ion<br /> collisions: collisional vs. radiative energy loss</a> [<a href="http://arxiv.org/pdf/1308.0617">PDF</a>]</h2>Shanshan Cao, Guang-You Qin, Steffen A. Bass<a name='more'></a><blockquote class="abstract">We study the dynamics of energy loss and flow of heavy quarks produced in ultra-relativistic heavy-ion collisions within the framework of a Langevin equation coupled to a (2+1)-dimensional viscous hydrodynamic model that simulates the space-time evolution of the produced hot and dense QCD matter. The classical Langevin approach is improved such that, apart from quasi-elastic scatterings, radiative energy loss is incorporated by treating gluon radiation as an additional force term. The hadronization of emitted heavy quarks is simulated via a hybrid fragmentation plus recombination model. Our calculation shows significant contribution from gluon radiation to heavy quark energy loss at high energies, and we find the recombination mechanism is important for heavy flavor meson production at intermediate energies. We present numerical results for the nuclear modification and elliptic flow of D mesons, which are consistent with measurements at both LHC and RHIC; predictions for B mesons are also provided.</blockquote>View original: <a href="http://arxiv.org/abs/1308.0617">http://arxiv.org/abs/1308.0617</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-72616956762881340282013-08-06T00:03:00.003-07:002013-08-06T00:03:59.193-07:001308.0736 (V. Uzhinsky)<h2 class="title"><a href="http://arxiv.org/abs/1308.0736">Toward UrQMD Model Description of pp and pC Interactions at High<br /> Energies</a> [<a href="http://arxiv.org/pdf/1308.0736">PDF</a>]</h2>V. Uzhinsky<a name='more'></a><blockquote class="abstract">It is found that UrQMD model version 3.3 does not describe NA61/SHINE Collaboration data on \pi-meson production in pp interactions at energies 20 - 80 GeV. At the same time, it describes quite well the NA49 Collaboration data on the meson production in pp and pC interactions at 158 GeV. The Collaborations do not consider feedback of \eta-meson decays. All versions of the UrQMD model assume that \eta-mesons are "stable". An inclusion of the decays into calculations leads to 2--3 % increase of the meson production which is not enough for description of the data. Possible ways of the model improvements are considered. Conclusions of the paper are: accounting of \eta-meson decays is not essential for a description of experimental data; a new tuning of the UrQMD model parameters is needed for a successful description of pp and pC interactions at high energies; inclusion of the low mass diffraction dissociation in the UrQMD model would be desirable.</blockquote>View original: <a href="http://arxiv.org/abs/1308.0736">http://arxiv.org/abs/1308.0736</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-75252470697745512013-08-06T00:03:00.001-07:002013-08-06T00:03:58.317-07:001308.1008 (X. Viñas et al.)<h2 class="title"><a href="http://arxiv.org/abs/1308.1008">Density dependence of the symmetry energy from neutron skin thickness in<br /> finite nuclei</a> [<a href="http://arxiv.org/pdf/1308.1008">PDF</a>]</h2>X. Viñas, M. Centelles, X. Roca-Maza, M. Warda<a name='more'></a><blockquote class="abstract">The density dependence of the symmetry energy around saturation density, characterized by the slope parameter L, is studied using information provided by the neutron skin thickness in finite nuclei. An estimate for L is obtained from experimental data on neutron skins extracted from antiprotonic atoms. We also discuss the ability of parity-violating elastic electron scattering to obtain information on the neutron skin thickness in 208Pb and to constrain the density dependence of the nuclear symmetry energy. The size and shape of the neutron density distribution of 208Pb predicted by mean-field models is briefly addressed. We conclude with a comparative overview of the L values predicted by several existing determinations.</blockquote>View original: <a href="http://arxiv.org/abs/1308.1008">http://arxiv.org/abs/1308.1008</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-38079704335026374432013-08-05T00:02:00.005-07:002013-08-05T00:02:56.948-07:001308.0347 (Lowell S. Brown et al.)<h2 class="title"><a href="http://arxiv.org/abs/1308.0347">Field Theory of the d+t -> n+alpha Reaction Dominated by a 5He* Unstable<br /> Particle</a> [<a href="http://arxiv.org/pdf/1308.0347">PDF</a>]</h2>Lowell S. Brown, Gerald M. Hale<a name='more'></a><blockquote class="abstract">An effective, non-relativistic field theory for low-energy d+t -> n+alpha reaction is presented. The theory assumes that the reaction is dominated by an intermediate 5He* unstable spin 3/2+ resonance. It involves two parameters in the coupling of the d+t and n+alpha particles to the unstable resonant state, and the resonance energy level -- only three real parameters in all. All Coulomb corrections to this process are computed. The resultant field theory is exactly solvable and provides an excellent description of the d+t fusion process.</blockquote>View original: <a href="http://arxiv.org/abs/1308.0347">http://arxiv.org/abs/1308.0347</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-50541217712595444532013-08-05T00:02:00.003-07:002013-08-05T00:02:56.218-07:001308.0348 (Gerald M. Hale et al.)<h2 class="title"><a href="http://arxiv.org/abs/1308.0348">Effective field theory as a limit of R-matrix theory for light nuclear<br /> reactions</a> [<a href="http://arxiv.org/pdf/1308.0348">PDF</a>]</h2>Gerald M. Hale, Lowell S. Brown, Mark W. Paris<a name='more'></a><blockquote class="abstract">We study the zero channel radius limit of Wigner's R-matrix theory for two cases, and show that it corresponds to non-relativistic effective quantum field theory. We begin with the simple problem of single-channel n-p elastic scattering in the 1S0 channel. The dependence of the R matrix width and level energy on the channel radius, "a" for fixed scattering length a0 and effective range r0 is determined. It is shown that these quantities have a simple pole for a critical value of the channel radius. The 3H(d,n)4He reaction cross section, analyzed with a two-channel effective field theory in the previous paper, is then examined using a two-channel, single-level R-matrix parametrization. The resulting S matrix is shown to be identical in these two representations in the limit that R-matrix channel radii are taken to zero. This equivalence is established by giving the relationship between the low-energy constants of the effective field theory (couplings and mass) and the R-matrix parameters (reduced width amplitudes and level energy). An excellent three-parameter fit to the observed astrophysical factor S is found for "unphysical" values of the reduced widths.</blockquote>View original: <a href="http://arxiv.org/abs/1308.0348">http://arxiv.org/abs/1308.0348</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-26673537900918890112013-08-05T00:02:00.001-07:002013-08-05T00:02:55.222-07:001308.0424 (Kenichi Yoshida)<h2 class="title"><a href="http://arxiv.org/abs/1308.0424">Spin-isospin response of deformed neutron-rich nuclei in a<br /> self-consistent Skyrme energy-density-functional approach</a> [<a href="http://arxiv.org/pdf/1308.0424">PDF</a>]</h2>Kenichi Yoshida<a name='more'></a><blockquote class="abstract">We develop a new framework of the self-consistent deformed proton-neutron quasiparticle-random-phase approximation (pnQRPA), formulated in the Hartree-Fock-Bogoliubov (HFB) single-quasiparticle basis. The same Skyrme force is used in both the HFB and pnQRPA calculations except in the proton-neutron particle-particle channel, where an S=1 contact force is employed. Numerical application is performed for Gamow-Teller (GT) strength distributions and $\beta$-decay rates in the deformed neutron-rich Zr isotopes located around the path of the rapid-neutron-capture process nucleosynthesis. It is found that the GT strength distributions are fragmented due to deformation. Furthermore we find that the momentum-dependent terms in the particle-hole residual interaction leads to a stronger collectivity of the GT giant resonance. The T=0 pairing enhances the low-lying strengths cooperatively with the T=1 pairing correlation, which shortens the $\beta$-decay half lives by at most an order of magnitude. The new calculation scheme reproduces well the observed isotopic dependence of the $\beta$-decay half lives of deformed $^{100-110}$Zr isotopes.</blockquote>View original: <a href="http://arxiv.org/abs/1308.0424">http://arxiv.org/abs/1308.0424</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-22022945150444597632013-08-04T00:04:00.005-07:002013-08-04T00:04:24.103-07:001308.0119 (Krishichayan et al.)<h2 class="title"><a href="http://arxiv.org/abs/1308.0119">Linear Polarization Measurements for High-Spin States in 146Gd</a> [<a href="http://arxiv.org/pdf/1308.0119">PDF</a>]</h2>Krishichayan, Rajashri Bhattacherjee, S. K. Basu, R. K. Bhowmik, A. Chakraborty, L. Chaturvedi, A. Dhal, U. Garg, S. S. Ghugre, R. Goswami, A. Jhingan, N. Madhvan, P. V. Madhusudhana Rao, S. Mukhopadhyay, S. Muralithar, S. Nath, N. S. Pattabiraman, S. Ray, S. Saha, M. Saha Sarkar, S. Sarkar, R. Singh, R. P. Singh, A. K. Sinha, R. K. Sinha, P. Sugathan, B. K. Yogi<a name='more'></a><blockquote class="abstract">A {\gamma}-ray linear polarization measurement has been performed to directly determine the parities for the levels in 146Gd nucleus. High-spin states in this nucleus were populated in a reaction 115In + 34S at 140 MeV incident energy. Linearly polarized {\gamma} - rays emitted from oriented states were measured using a Compton polarimeter consisting of an array of 8 Compton-suppressed Clover detectors. Unambiguous assignments of the spin and parity have been made for most of the observed levels and changes made in the previously reported spin-parity assignments for a few levels. Shell model calculations performed with judicious truncation over the {\pi}(gdsh) valence space interpret the structure of only the low-lying levels up to J{\pi} = 19+ and 9-. N = 82 neutron-core breaking is found to be essential for high spin states with excitation energies Ex > 7 MeV.</blockquote>View original: <a href="http://arxiv.org/abs/1308.0119">http://arxiv.org/abs/1308.0119</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-89295764098472301802013-08-04T00:04:00.003-07:002013-08-04T00:04:23.064-07:001308.0162 (A. Astier et al.)<h2 class="title"><a href="http://arxiv.org/abs/1308.0162">High-spin structures of 88Kr and 89Rb: Evolution from collective to<br /> single-particle behaviors</a> [<a href="http://arxiv.org/pdf/1308.0162">PDF</a>]</h2>A. Astier, M. -G. Porquet, Ts. Venkova, G. Duchene, F. Azaiez, D. Curien, I. Deloncle, O. Dorvaux, B. J. P. Gall, N. Redon, M. Rousseau, O. Stezowski<a name='more'></a><blockquote class="abstract">The high-spin states of the two neutron-rich nuclei, 88Kr and 89R have been studied from the 18O + 208Pb fusion-fission reaction. Their level schemes were built from triple gamma-ray coincidence data and gamma-gamma angular correlations were analyzed in order to assign spin and parity values to most of the observed states. The two levels schemes evolve from collective structures to single-particle excitations as a function of the excitation energy. Comparison with results of shell-model calculations gives the specific proton and neutron configurations which are involved to generate the angular momentum along the yrast lines.</blockquote>View original: <a href="http://arxiv.org/abs/1308.0162">http://arxiv.org/abs/1308.0162</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-10495554246485396352013-08-04T00:04:00.001-07:002013-08-04T00:04:22.143-07:001308.0207 (M. Saha Sarkar et al.)<h2 class="title"><a href="http://arxiv.org/abs/1308.0207">Understanding Nuclei in the upper sd - shell</a> [<a href="http://arxiv.org/pdf/1308.0207">PDF</a>]</h2>M. Saha Sarkar, Abhijit Bisoi, Sudatta Ray, Ritesh Kshetri, S. Sarkar<a name='more'></a><blockquote class="abstract">Nuclei in the upper-$sd$ shell usually exhibit characteristics of spherical single particle excitations. In the recent years, employment of sophisticated techniques of gamma spectroscopy has led to observation of high spin states of several nuclei near A$\simeq$ 40. In a few of them multiparticle, multihole rotational states coexist with states of single particle nature. We have studied a few nuclei in this mass region experimentally, using various campaigns of the Indian National Gamma Array setup. We have compared and combined our empirical observations with the large-scale shell model results to interpret the structure of these nuclei. Indication of population of states of large deformation has been found in our data. This gives us an opportunity to investigate the interplay of single particle and collective degrees of freedom in this mass region.</blockquote>View original: <a href="http://arxiv.org/abs/1308.0207">http://arxiv.org/abs/1308.0207</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-78101338553475516602013-08-01T00:32:00.003-07:002013-08-01T00:32:58.349-07:001307.7923 (Ulf-G. Meißner)<h2 class="title"><a href="http://arxiv.org/abs/1307.7923">Nuclear lattice simulations: Status and perspectives</a> [<a href="http://arxiv.org/pdf/1307.7923">PDF</a>]</h2>Ulf-G. Meißner<a name='more'></a><blockquote class="abstract">I review the present status of nuclear lattice simulations. This talk is dedicated to the memory of Gerald E. Brown.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7923">http://arxiv.org/abs/1307.7923</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-33876043293269438852013-08-01T00:32:00.001-07:002013-08-01T00:32:57.438-07:001307.8178 (M. W. Ahmed et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.8178">Parity Violation in Photonuclear Reactions at HIGS -- Submission to<br /> Snowmass 2013: Intensity Frontier</a> [<a href="http://arxiv.org/pdf/1307.8178">PDF</a>]</h2>M. W. Ahmed, A. E. Champagne, B. R. Holstein, C. R. Howell, W. M. Snow, R. P. Springer, W. K. Wu<a name='more'></a><blockquote class="abstract">We discuss the scientific motivation, possible experiments, and beam requirements for measurements of parity violation in photonuclear reactions at an intensity upgraded HIGS facility, HIGS2.</blockquote>View original: <a href="http://arxiv.org/abs/1307.8178">http://arxiv.org/abs/1307.8178</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-10557917285278806742013-07-31T00:19:00.005-07:002013-07-31T00:19:02.960-07:001307.7746 (J. Piekarewicz)<h2 class="title"><a href="http://arxiv.org/abs/1307.7746">Symmetry Energy Constraints from Giant Resonances: A Theoretical<br /> Overview</a> [<a href="http://arxiv.org/pdf/1307.7746">PDF</a>]</h2>J. Piekarewicz<a name='more'></a><blockquote class="abstract">Giant resonances encapsulate the dynamic response of the nuclear ground state to external perturbations. As such, they offer a unique view of the nucleus that is often not accessible otherwise. Although interesting in their own right, giant resonances are also enormously valuable in providing stringent constraints on the equation of state of asymmetric matter. We this view in mind, we focus on two modes of excitation that are essential in reaching this goal: the isoscalar giant monopole resonance (GMR) and the isovector giant dipole resonance (GDR). GMR energies in heavy nuclei are sensitive to the symmetry energy because they probe the incompressibility of neutron-rich matter. Unfortunately, access to the symmetry energy is hindered by the relatively low neutron-proton asymmetry of stable nuclei. Thus, the measurement of GMR energies in exotic nuclei is strongly encouraged. In the case of the GDR, we find the electric dipole polarizability of paramount importance. Indeed, the electric dipole polarizability appears as one of two laboratory observables -- with the neutron-skin thickness being the other -- that are highly sensitive to the density dependence of the symmetry energy. Finally, we identify the softness of skin and the nature of the pygmy resonance as important unsolved problems in nuclear structure.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7746">http://arxiv.org/abs/1307.7746</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-52454469549327789102013-07-31T00:19:00.003-07:002013-07-31T00:19:02.231-07:001307.7777 (MAJORANA Collaboration et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7777">The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay<br /> of Germanium-76</a> [<a href="http://arxiv.org/pdf/1307.7777">PDF</a>]</h2>MAJORANA Collaboration, S. R. Elliott, N. Abgrall, E. Aguayo, F. T. Avignone III, A. S. Barabash, F. E. Bertrand, M. Boswell, V. Brudanin, M. Busch, A. S. Caldwell, Y-D. Chan, C. D. Christofferson, D. C. Combs, J. A. Detwiler, P. J. Doe, Yu. Efremenko, V. Egorov, H. Ejiri, J. Esterline, J. E. Fast, P. Finnerty, F. M. Fraenkleo, A. Galindo-Uribarri, G. K. Giovanetti, J. Goett, M. P. Green, J. Gruszko, V. E. Guiseppe, K. Gusev, A. L. Hallin, R. Hazama, A. Hegai, R. Henning, E. W. Hoppe, S. Howard, M. A. Howe, K. J. Keeter, M. F. Kidd, O. Kochetov, S. I. Konovalov, R. T. Kouzes, B. D. LaFerriere, J. Leon, L. E. Leviner, J. C. Loach, S. MacMullin, R. D. Martin, S. Mertens, L. Mizouni, M. Nomachi, J. L. Orrell, C. OShaughnessy, N. R. Overman, D. G. Phillips II, A. W. P. Poon, K. Pushkin, D. C. Radford, K. Rielage, R. G. H. Robertson, M. C. Ronquest, A. G. Schubert, B. Shanks, T. Shima, M. Shirchenko, K. J. Snavely, N. Snyder, A. Soin, J. Strain, A. M. Suriano, V. Timkin, W. Tornow, R. L. Varner, S. Vasilyev, K. Vetter, K. Vorren, B. R. White, J. F. Wilkerson, W. Xu, E. Yakushev, A. R. Young, C. -H. Yu, V. Yumatov<a name='more'></a><blockquote class="abstract">The {\sc Majorana} collaboration is searching for neutrinoless double beta decay using $^{76}$Ge, which has been shown to have a number of advantages in terms of sensitivities and backgrounds. The observation of neutrinoless double-beta decay would show that lepton number is violated and that neutrinos are Majorana particles and would simultaneously provide information on neutrino mass. Attaining sensitivities for neutrino masses in the inverted hierarchy region, $15 - 50$ meV, will require large, tonne-scale detectors with extremely low backgrounds, at the level of $\sim$1 count/t-y or lower in the region of the signal. The {\sc Majorana} collaboration, with funding support from DOE Office of Nuclear Physics and NSF Particle Astrophysics, is constructing the {\sc Demonstrator}, an array consisting of 40 kg of p-type point-contact high-purity germanium (HPGe) detectors, of which $\sim$30 kg will be enriched to 87% in $^{76}$Ge. The {\sc Demonstrator} is being constructed in a clean room laboratory facility at the 4850' level (4300 m.w.e.) of the Sanford Underground Research Facility (SURF) in Lead, SD. It utilizes a compact graded shield approach with the inner portion consisting of ultra-clean Cu that is being electroformed and machined underground. The primary aim of the {\sc Demonstrator} is to show the feasibility of a future tonne-scale measurement in terms of backgrounds and scalability.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7777">http://arxiv.org/abs/1307.7777</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-35075901676603098572013-07-31T00:19:00.001-07:002013-07-31T00:19:01.438-07:001307.8099 (Kiminad A. Mamo et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.8099">Spin Polarized Photons and Di-leptons from Axially Charged Plasma</a> [<a href="http://arxiv.org/pdf/1307.8099">PDF</a>]</h2>Kiminad A. Mamo, Ho-Ung Yee<a name='more'></a><blockquote class="abstract">Axial charge in a QCD plasma is P- and CP-odd. We propose and study P- and CP-odd observables in photon and di-lepton emissions from an axially charged QCD plasma, which may provide possible experimental evidences of axial charge fluctuation and triangle anomaly in the plasma created in heavy-ion collisions. Our observables measure spin alignments of the emitted photons and di-leptons, and are shown to be related to the imaginary part of chiral magnetic conductivity at finite frequency-momentum, which ultimately arises from the underlying triangle anomaly of the QCD plasma with a finite axial charge density. We present an exemplar computation of these observables in strongly coupled regime using AdS/CFT correspondence.</blockquote>View original: <a href="http://arxiv.org/abs/1307.8099">http://arxiv.org/abs/1307.8099</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-73196850753643102232013-07-30T00:08:00.015-07:002013-07-30T00:08:50.419-07:001307.7225 (Elena Kokoulina On behalf of the SVD-2 Collaboration)<h2 class="title"><a href="http://arxiv.org/abs/1307.7225">Evidence for a pion condensate formation in pp interactions at U-70</a> [<a href="http://arxiv.org/pdf/1307.7225">PDF</a>]</h2>Elena Kokoulina On behalf of the SVD-2 Collaboration<a name='more'></a><blockquote class="abstract">A high multiplicity study (project Thermalization, experiment E-190) is carried out on U-70 accelerator at IHEP (Protvino, Russia). This project is aimed at searching for collective phenomena. It is known that pions are mainly produced at the 50 GeV-proton beam accelerator. Their mean energy decreases while multiplicity increasing. Bose-Einstein condensate (BEC) can be formed in this system. The theoretical and experimental studies of BEC have been performed since 70es. Within the framework of an ideal pion gas model M. Gorenstein and V. Begun have shown that sharp growth of fluctuations of the neutral pion number will be a signal of BEC formation with the increase of the total multiplicity (neutral and charged particle sum). SVD-2 Collaboration (JINR, IHEP and SINP MSU) investigated fluctuations of the neutral pion number in pp interactions at 50 GeV/c incident beam on U-70 versus the total multiplicity and has revealed noticeable growth of the scaled variance with the total multiplicity increase. The growth of these fluctuations reaches more than 7 standard deviations for the scaled variance at the total multiplicity about 30 pions as opposed to the tendency for the simulated events. This growth has been observed both in the registered photons and restored neutral pions.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7225">http://arxiv.org/abs/1307.7225</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-12082756495739443172013-07-30T00:08:00.013-07:002013-07-30T00:08:48.849-07:001307.7294 (P. Descouvemont et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7294">Toward a microscopic description of reactions involving exotic nuclei</a> [<a href="http://arxiv.org/pdf/1307.7294">PDF</a>]</h2>P. Descouvemont, M. S. Hussein<a name='more'></a><blockquote class="abstract">We propose an extension of the Continuum Discretized Coupled Channels (CDCC) method, where the projectile is described by a microscopic cluster model. This microscopic generalization (MCDCC) only relies on nucleon-target interactions, and therefore presents an important predictive power. Core excitations can be included without any further parameter. As an example we investigate the $\lipb$ elastic scattering at $E_{lab}=27$ and 35 MeV. The $^7$Li nucleus is known to present an $\alpha+t$ cluster structure, and is well described by the Resonating Group Method. An excellent agreement is obtained for the $\lipb$ elastic cross sections, provided that breakup channels are properly included. We also present an application to inelastic scattering, and discuss future applications of the MCDCC.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7294">http://arxiv.org/abs/1307.7294</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-21917660404083642592013-07-30T00:08:00.011-07:002013-07-30T00:08:47.928-07:001307.7361 (B. S. Schlimme et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7361">Measurement of the neutron electric to magnetic form factor ratio at Q2<br /> = 1.58 GeV2 using the reaction 3He(e,e'n)pp</a> [<a href="http://arxiv.org/pdf/1307.7361">PDF</a>]</h2>B. S. Schlimme, P. Achenbach, C. A. Ayerbe Gayoso, J. C. Bernauer, R. Böhm, D. Bosnar, Th. Challand, M. O. Distler, L. Doria, F. Fellenberger, H. Fonvieille, M. Gómez Rodríguez, P. Grabmayr, T. Hehl, W. Heil, D. Kiselev, J. Krimmer, M. Makek, H. Merkel, D. G. Middleton, U. Müller, L. Nungesser, B. A. Ott, J. Pochodzalla, M. Potokar, S. Sánchez Majos, M. M. Sargsian, I. Sick, S. Širca, M. Weinriefer, M. Wendel, C. J. Yoon<a name='more'></a><blockquote class="abstract">A measurement of beam helicity asymmetries in the reaction 3He(e,e'n)pp has been performed at the Mainz Microtron in quasielastic kinematics in order to determine the electric to magnetic form factor ratio of the neutron, GEn/GMn, at a four momentum transfer Q2 = 1.58 GeV2. Longitudinally polarized electrons were scattered on a highly polarized 3He gas target. The scattered electrons were detected with a high-resolution magnetic spectrometer, and the ejected neutrons with a dedicated neutron detector composed of scintillator bars. To reduce systematic errors data were taken for four different target polarization orientations allowing the determination of GEn/GMn from a double ratio. We find mu_n GEn/GMn = 0.250 +/- 0.058(stat.) +/- 0.017 (sys.).</blockquote>View original: <a href="http://arxiv.org/abs/1307.7361">http://arxiv.org/abs/1307.7361</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-7744296652577645112013-07-30T00:08:00.009-07:002013-07-30T00:08:40.864-07:001307.7373 (Y. Ito et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7373">Single-reference high-precision mass measurement with a multi-reflection<br /> time-of-flight mass spectrograph</a> [<a href="http://arxiv.org/pdf/1307.7373">PDF</a>]</h2>Y. Ito, P. Schury, M. Wada, S. Naimi, T. Sonoda, H. Mita, F. Arai, A. Takamine, K. Okada, A. Ozawa, H. Wollnik<a name='more'></a><blockquote class="abstract">A multi-reflection time-of-flight mass spectrograph, competitive with Penning trap mass spectrometers, has been built at RIKEN. We have performed a first online mass measurement, using 8Li+ (T1/2 = 838 ms). A new analysis method has been realized, with which, using only 12C+ references, the mass excess of 8Li was accurately determined to be 20947.6(15)(34) keV (dm/m = 6.6 x 10-7). The speed, precision and accuracy of this first online measurement exemplifies the potential for using this new type of mass spectrograph for precision measurements of short-lived nuclei.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7373">http://arxiv.org/abs/1307.7373</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-3128009168775853122013-07-30T00:08:00.007-07:002013-07-30T00:08:40.127-07:001307.7388 (I. A. Qattan et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7388">Up- and Down-Quark Contributions to the Nucleon Form Factors</a> [<a href="http://arxiv.org/pdf/1307.7388">PDF</a>]</h2>I. A. Qattan, J. Arrington<a name='more'></a><blockquote class="abstract">Recent measurements of the neutron's electric to magnetic form factors ratio, R_n= \mu_n G_E^n/G_M^n, up to 3.4 (GeV/c)^2 combined with existing R_p= \mu_p G_E^p/G_M^p measurements in the same Q^2 range allowed, for the first time, a separation of the up- and down-quark contributions to the form factors at high Q^2, as presented by Cates, et al. Our analysis expands on the original work by including additional form factor data, applying two-photon exchange (TPE) corrections, and accounting for the uncertainties associated with all of the form factor measurements</blockquote>View original: <a href="http://arxiv.org/abs/1307.7388">http://arxiv.org/abs/1307.7388</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-53259937578025721202013-07-30T00:08:00.005-07:002013-07-30T00:08:39.132-07:001307.7568 (A. Beraudo et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7568">Heavy flavour in nucleus-nucleus collisions at RHIC and LHC: a Langevin<br /> approach</a> [<a href="http://arxiv.org/pdf/1307.7568">PDF</a>]</h2>A. Beraudo, A. De Pace, M. Monteno, F. Prino, W. M. Alberico, A. Molinari, M. Nardi<a name='more'></a><blockquote class="abstract">A snapshot of the results for heavy-flavour observables in heavy-ion (AA) collisions at RHIC and LHC obtained with our transport calculations is displayed. The initial charm and beauty production is simulated through pQCD tools (POWHEG+PYTHIA) and is validated through the comparison with data from pp collisions. The propagation of c and b quarks in the medium formed in heavy-ion collisions is studied through a transport setup based on the relativistic Langevin equation. With respect to past works we perform a more systematic study, providing results with different choices of transport coefficients, either from weak-coupling calculations or from lattice-QCD simulations. Our findings are compared to a rich set of experimental data (D-mesons, non-photonic electrons, non-prompt J/\psi's) which have meanwhile become accessible.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7568">http://arxiv.org/abs/1307.7568</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-35530105063022387272013-07-30T00:08:00.003-07:002013-07-30T00:08:38.089-07:001307.7670 (Julia Riede et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7670">Numerical simulation of non-steady state neutron kinetics of the TRIGA<br /> Mark II reactor Vienna</a> [<a href="http://arxiv.org/pdf/1307.7670">PDF</a>]</h2>Julia Riede, Helmuth Boeck<a name='more'></a><blockquote class="abstract">This paper presents an algorithm for numerical simulations of non-steady states of the TRIGA MARK II reactor in Vienna, Austria. The primary focus of this work has been the development of an algorithm which provides time series of integral neutron flux after reactivity changes introduced by perturbations without the usage of thermal-hydraulic / neutronic numerical code systems for the TRIGA reactor in Vienna, Austria. The algorithm presented takes into account both external reactivity changes as well as internal reactivity changes caused by feedback mechanisms like effects caused by temperature changes of the fuel and poisoning effects. The resulting time series have been compared to experimental results.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7670">http://arxiv.org/abs/1307.7670</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-43918344682635687902013-07-30T00:08:00.001-07:002013-07-30T00:08:37.295-07:001307.7689 (Julia Riede et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7689">In-situ gamma spectrometry measurements of time-dependent Xenon-135<br /> inventory in the TRIGA Mark II reactor Vienna</a> [<a href="http://arxiv.org/pdf/1307.7689">PDF</a>]</h2>Julia Riede, Helmuth Boeck<a name='more'></a><blockquote class="abstract">In this work, it has been shown that the time dependent Xe-135 inventory in the TRIGA Mark II reactor in Vienna, Austria can be measured via gamma spectrometry even in the presence of strong background radiation. It is focussing on the measurement of (but not limited to) the nuclide Xe-135. The time dependent Xe-135 inventory of the TRIGA Mark II reactor Vienna has been measured using a temporary beam line between one fuel element of the core placed onto the thermal column after shutdown and a detector system located just above the water surface of the reactor tank. For the duration of one week, multiple gamma ray spectra were recorded automatically, starting each afternoon after reactor shutdown until the next morning. One measurement series has been recorded over the weekend. The Xe-135 peaks were extracted from a total of 1227 recorded spectra using an automated peak search algorithm and analyzed for their time-dependent properties. Although the background gamma radiation present in the core after shutdown was large especially in the lower energy range, the Xe-135 peak located at 249.8 keV could be extracted from the most spectra where present and could be compared to theoretical calculations.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7689">http://arxiv.org/abs/1307.7689</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-16084242747012971722013-07-29T00:02:00.003-07:002013-07-29T00:02:43.664-07:001307.7034 (M. Klasen et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7034">How robust is a thermal photon interpretation of the ALICE low-p_T data?</a> [<a href="http://arxiv.org/pdf/1307.7034">PDF</a>]</h2>M. Klasen, C. Klein-Boesing, F. Koenig, J. P. Wessels<a name='more'></a><blockquote class="abstract">We present a rigorous theoretical analysis of the ALICE measurement of low-p_T direct-photon production in central lead-lead collisions at the LHC with a centre-of-mass energy of \sqrt{s_{NN}}=2.76 TeV. Using NLO QCD, we compute the relative contributions to prompt-photon production from different initial and final states and the theoretical uncertainties coming from independent variations of the renormalisation and factorisation scales, the nuclear parton densities and the fragmentation functions. Based on different fits to the unsubtracted and prompt-photon subtracted ALICE data, we consistently find T = 304 \pm 58 MeV and 309 \pm 64 MeV for the effective temperature of the quark-gluon plasma (or hot medium) at p_T \in [0.8;2.2] GeV and p_T \in [1.5;3.5] GeV as well as a power-law (p_T^{-4}) behavior for p_T > 4 GeV as predicted by QCD hard scattering.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7034">http://arxiv.org/abs/1307.7034</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-63032346695812367782013-07-29T00:02:00.001-07:002013-07-29T00:02:42.763-07:001307.7097 (M. Elnimr et al.)<h2 class="title"><a href="http://arxiv.org/abs/1307.7097">The OscSNS White Paper</a> [<a href="http://arxiv.org/pdf/1307.7097">PDF</a>]</h2>M. Elnimr, I. Stancu, M. Yeh, R. Svoboda, M. J. Wetstein, F. G. Garcia, B. Osmanov, H. Ray, R. Tayloe, J. Boissevain, G. T. Garvey, W. Huelsnitz, W. C. Louis, G. B. Mills, Z. Pavlovic, R. Van de Water, D. H. White, R. Imlay, B. P. Roe, R. Allen, Y. Efremenko, T. Gabriel, T. Handler, Y. Kamyshkov, F. T. Avignone, S. R. Mishra, C. Rosenfeld, J. M. Link<a name='more'></a><blockquote class="abstract">There exists a need to address and resolve the growing evidence for short-baseline neutrino oscillations and the possible existence of sterile neutrinos. Such non-standard particles require a mass of $\sim 1$ eV/c$^2$, far above the mass scale associated with active neutrinos, and were first invoked to explain the LSND $\bar \nu_\mu \rightarrow \bar \nu_e$ appearance signal. More recently, the MiniBooNE experiment has reported a $2.8 \sigma$ excess of events in antineutrino mode consistent with neutrino oscillations and with the LSND antineutrino appearance signal. MiniBooNE also observed a $3.4 \sigma$ excess of events in their neutrino mode data. Lower than expected neutrino-induced event rates using calibrated radioactive sources and nuclear reactors can also be explained by the existence of sterile neutrinos. Fits to the world's neutrino and antineutrino data are consistent with sterile neutrinos at this $\sim 1$ eV/c$^2$ mass scale, although there is some tension between measurements from disappearance and appearance experiments. In addition to resolving this potential major extension of the Standard Model, the existence of sterile neutrinos will impact design and planning for all future neutrino experiments. It should be an extremely high priority to conclusively establish if such unexpected light sterile neutrinos exist. The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, built to usher in a new era in neutron research, provides a unique opportunity for US science to perform a definitive world-class search for sterile neutrinos.</blockquote>View original: <a href="http://arxiv.org/abs/1307.7097">http://arxiv.org/abs/1307.7097</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0tag:blogger.com,1999:blog-1082776018106726955.post-59239410698248412902013-07-26T00:48:00.005-07:002013-07-26T00:48:44.492-07:001305.2407 (M. B. Gay Ducati et al.)<h2 class="title"><a href="http://arxiv.org/abs/1305.2407">Diffractive photoproduction of radially excited psi(2S) mesons in<br /> photon-Pomeron reactions in PbPb collisions at the CERN LHC</a> [<a href="http://arxiv.org/pdf/1305.2407">PDF</a>]</h2>M. B. Gay Ducati, M. T. Griep, M. V. T. Machado<a name='more'></a><blockquote class="abstract">In this work we investigate the photoproduction of radially excited vector mesons off nuclei in heavy ion relativistic collisions. In particular, we analyze the exclusive photoproduction of psi(2S) off nuclei, evaluating the coherent and the incoherent contributions to that process. The theoretical framework used in the present analysis is the light-cone dipole formalism and predictions are done for PbPb collisions at the CERN-LHC energy of 2.76 TeV. The theoretical uncertainties are analyzed and comparison is also done to the recent ALICE Collaboration data for the psi(1S) state photoproduction.</blockquote>View original: <a href="http://arxiv.org/abs/1305.2407">http://arxiv.org/abs/1305.2407</a>C.P.R.http://www.blogger.com/profile/13598012384534951656noreply@blogger.com0