Search results for "Nucleon"
showing 10 items of 1041 documents
Nuclear medium effects in structure functions
2012
We discuss the nuclear-medium effects in the weak structure functions F2(x,Q2) and F3,(x,Q2) in the charged current neutrino and antineutrino induced deep inelastic reactions in some nuclei which are being used in the present or proposed neutrino oscillation experiments. Our study of the medium effects has been done using relativistic nuclear spectral functions which incorporates Fermi motion, binding energy and nucleon correlations. We also consider the pion and rho meson cloud contributions calculated from a microscopic model for meson-nucleus self-energies. Using these structure functions, the results for the differential cross section have been obtained and compared with some of the ava…
Precision mass measurements for nuclear astro- and neutrino physics
2012
Nuclear masses are indispensable ingredients in numerous physics applications ranging from nuclear structure physics, where, e.g., the shell closures and nucleon correlation energies can be studied by accurate mass measurements, via the nuclear astrophysics, where the masses of nuclei far from the valley of β-stability determine the pathways of, e.g., rp-and r-processes of nucleosynthesis in stars, to tests of the standard model and fundamental interactions, where, e.g., the very-accurate masses of parent and superallowed β-decay daughter nuclei serve as one of inputs for the checking of the unitarity of the CKM quark-mixing matrix. In this review we focus on recent direct mass measurements…
Reaction dynamics and nuclear structure studies via deep inelastic collisions with heavy-ions: spin and parity assignment in49Ca
2011
The population and gamma decay of neutron rich nuclei around 48Ca has been measured at Legnaro National Laboratory with the PRISMA-CLARA setup, using deep-inelastic collisions (DIC) on 64Ni, at an energy approximately twice the Coulomb barrier. The reaction properties of the main products are investigated, focusing on total cross sections and angular distributions both integrated in energy and associated to the population of specific excited states. Gamma spectroscopy studies are also performed, giving evidence, for the first time in transfer reactions with heavy ions, of a large spin alignment (~70%), perpendicular to the reaction plane. This makes possible the use of angular distributions…
High-precision mass measurements for the rp-process at JYFLTRAP
2017
The double Penning trap JYFLTRAP at the University of Jyvaskyla has been successfully used to achieve high-precision mass measurements of nuclei involved in the rapid proton-capture (rp) process. A precise mass measurement of 31 Cl is essential to estimate the waiting point condition of 30 S in the rp-process occurring in type I x-ray bursts (XRBs). The mass-excess of 31 C1 measured at JYFLTRAP, -7034.7(3.4) keV, is 15 more precise than the value given in the Atomic Mass Evaluation 2012. The proton separation energy S p determined from the new mass-excess value confirmed that 30 S is a waiting point, with a lower-temperature limit of 0.44 GK. The mass of 52 Co effects both 51 Fe( p,γ ) 52 C…
Nuclear structure of Te isotopes beyond neutron magic number N=82
2021
15 pags., 10 figs., 4 tabs.
Nucleon isovector charges and twist-2 matrix elements with Nf=2+1 dynamical Wilson quarks
2019
We present results from a lattice QCD study of nucleon matrix elements at vanishing momentum transfer for local and twist-2 isovector operator insertions. Computations are performed on gauge ensembles with nonperturbatively improved ${N}_{f}=2+1$ Wilson fermions, covering four values of the lattice spacing and pion masses down to ${M}_{\ensuremath{\pi}}\ensuremath{\approx}200\text{ }\text{ }\mathrm{MeV}$. Several source-sink separations (typically $\ensuremath{\sim}1.0$ to $\ensuremath{\sim}1.5\text{ }\text{ }\mathrm{fm}$) allow us to assess excited-state contamination. Results on individual ensembles are obtained from simultaneous two-state fits across all observables and all available sou…
Enhanced Quadrupole and Octupole Strength in Doubly Magic Sn132
2018
The first 2+ and 3- states of the doubly magic nucleus Sn132 are populated via safe Coulomb excitation employing the recently commissioned HIE-ISOLDE accelerator at CERN in conjunction with the highly efficient MINIBALL array. The Sn132 ions are accelerated to an energy of 5.49 MeV/nucleon and impinged on a Pb206 target. Deexciting γ rays from the low-lying excited states of the target and the projectile are recorded in coincidence with scattered particles. The reduced transition strengths are determined for the transitions 0g.s.+→21+, 0g.s.+→31-, and 21+→31- in Sn132. The results on these states provide crucial information on cross-shell configurations which are determined within large-sca…
Comparison of Fragmentation Functions for Jets Dominated by Light Quarks and Gluons from pp and Pb+Pb Collisions in ATLAS
2019
Charged-particle fragmentation functions for jets azimuthally balanced by a high-transverse-momentum, prompt, isolated photon are measured in 25 pb^{-1} of pp and 0.49 nb^{-1} of Pb+Pb collision data at 5.02 TeV per nucleon pair recorded with the ATLAS detector at the Large Hadron Collider. The measurements are compared to predictions of Monte Carlo generators and to measurements of inclusively selected jets. In pp collisions, a different jet fragmentation function in photon-tagged events from that in inclusive jet events arises from the difference in fragmentation between light quarks and gluons. The ratios of the fragmentation functions in Pb+Pb events to that in pp events are used to e…
Medium-Induced Modification of Z -Tagged Charged Particle Yields in Pb+Pb Collisions at 5.02 TeV with the ATLAS Detector
2021
The yield of charged particles opposite to a Z boson with large transverse momentum (p_{T}) is measured in 260 pb^{-1} of pp and 1.7 nb^{-1} of Pb+Pb collision data at 5.02 TeV per nucleon pair recorded with the ATLAS detector at the Large Hadron Collider. The Z boson tag is used to select hard-scattered partons with specific kinematics, and to observe how their showers are modified as they propagate through the quark-gluon plasma created in Pb+Pb collisions. Compared with pp collisions, charged-particle yields in Pb+Pb collisions show significant modifications as a function of charged-particle p_{T} in a way that depends on event centrality and Z boson p_{T}. The data are compared with a…
Towards an Improved Measurement of the Proton Magnetic Moment
2017
The BASE collaboration performed the most precise measurement of the proton magnetic moment. By applying the so-called double Penning-trap method with a single proton a fractional precision of 3.3 parts-per-billion was reached. This article describes the primary limitations of the last measurement and discusses improvements to reach the sub-parts-per-billion level.