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Neutrino scattering with nuclei - Theory of low energy nuclear effects and its applications

Leitner, T.; Buss, O.; Mosel, U.; Alvarez-Ruso, L.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/09/2008
Relevância na Pesquisa
45.88%
Current long baseline experiments aim at measuring neutrino oscillation parameters with a high precision. A critical quantity is the neutrino energy which can not be measured directly but has to be reconstructed from the observed hadrons. A good knowledge of neutrino-nucleus interactions is thus necessary to minimize the systematic uncertainties in neutrino fluxes, backgrounds and detector responses. In particular final-state interactions inside the target nucleus modify considerably the particle yields through rescattering, charge-exchange and absorption. Nuclear effects can be described with our coupled channel GiBUU transport model where the neutrino first interacts with a bound nucleon producing secondary particles which are then transported out of the nucleus. In this contribution, we give some examples for the application of our model focusing in particular on the MiniBooNE and K2K experiments.; Comment: To appear in the proceedings of the 10th International Workshop on Neutrino Factories, Super beams and Beta beams (NUFACT08), June 30 - July 5 2008, Valencia, Spain

Neutrino beams as a probe of the nuclear isospin and spin-isospin excitations

Lazauskas, R.; Volpe, C.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.88%
We explore the possibility of performing nuclear structure studies using low energy neutrino beams. In particular, low energy beta-beams and conventional sources (muon decay-at-rest) are considered. We present results on the total charged-current as well as flux-averaged cross sections associated to electron (anti)-neutrino scattering on oxygen, iron, molybdenum and lead, as typical examples. It is shown that by using neutrinos from low energy beta-beams, information on forbidden states, in particular the spin-dipole, could be extracted.; Comment: 13 pages, 4 figures, 3 tables

Nuclear EMC Effect in a Statistical Model

Zhang, Yunhua; Shao, Lijing; Ma, Bo-Qiang
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 02/09/2009
Relevância na Pesquisa
45.88%
A simple statistical model in terms of light-front kinematic variables is used to explain the nuclear EMC effect in the range $x \in [0.2,~0.7]$, which was constructed by us previously to calculate the parton distribution functions (PDFs) of the nucleon. Here, we treat the temperature $T$ as a parameter of the atomic number $A$, and get reasonable results in agreement with the experimental data. Our results show that the larger $A$, the lower $T$ thus the bigger volume $V$, and these features are consistent with other models. Moreover, we give the predictions of the quark distribution ratios, \emph{i.e.}, $q^A(x) / q^D(x)$, $\bar{q}^A(x) / \bar{q}^D(x)$, and $s^A(x) / s^D(x)$, and also the gluon ratio $g^A(x) / g^D(x)$ for iron as an example. The predictions are different from those by other models, thus experiments aiming at measuring the parton ratios of antiquarks, strange quarks, and gluons can provide a discrimination of different models.; Comment: 26 latex pages, 3 figures

Profiling hot and dense nuclear medium with high transverse momentum hadrons produced in d+Au and Au+Au collisions by the PHENIX experiment at RHIC

Sakaguchi, Takao; collaboration, for the PHENIX
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 06/08/2013
Relevância na Pesquisa
45.88%
PHENIX measurements of high transverse momentum ($p_T$) identified hadrons in $d$+Au and Au+Au collisions are presented. The nuclear modification factors ($R_{d{\rm A}}$ and $R_{\rm AA}$) for $\pi^0$ and $\eta$ are found to be very consistent in both collision systems, respectively. Using large amount of $p+p$ and Au+Au datasets, the fractional momentum loss ($S_{\rm loss}$) and the path-length dependent yield of $\pi^0$ in Au+Au collisions are obtained. The hadron spectra in the most central $d$+Au and the most peripheral Au+Au collisions are studied. The spectra shapes are found to be similar in both systems, but the yield is suppressed in the most peripheral Au+Au collisions.; Comment: 4 pages, 5 figures, talk presented at the International Nuclear Physics Conference 2013, held in Florence, Italy, on June 2 - 7, 2013

Phenomenological model of the Kaonic Nuclear Cluster K^-pp in the ground state

Ivanov, A. N.; Kienle, P.; Marton, J.; Widmann, E.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.88%
A phenomenological model is proposed for the analysis of the properties of the Kaonic Nuclear Cluster (KNC) Kpp in its ground state. Inside the KNC K^-pp we describe the relative motion of the protons in the pp pair and the motion of the K^- meson relative to the pp pair in terms of wave functions of 3-dimensional harmonic oscillators. The interaction strength is parameterised in our model by the frequency of the longitudinal oscillation of the K^- meson relative to the pp pair. This parameter was determined with the binding energy and width of the strange baryon Lambda(1405) by assuming that it is a bound state of the K^-p pair. In terms of this interaction strength we calculate the binding energy epsilon_(Kpp) = - 118 MeV, the partial widths of non-pionic decay channels and the total width, Gamma_(Kpp) = 58 MeV. This agrees well with the experimental data by the FINUDA Collaboration (PRL 94, 212303 (2005)): epsilon_exp = - 115(+6/-5) MeV and Gamma_exp = 67(+14/-11) MeV. The discrepancy with the results, obtained by Akaishi and Yamazaki within the potential model approach, is discussed.; Comment: 22 pages, 6 figures, Latex, The amplitudes of elastic and inelastic K^-pp scattering are calculated using the chiral Lagrangian with SU(3)xSU(3) chiral symmetry and derivative meson-baryon couplings. The theoretical binding energy and width of the K^-pp bound state agree well with the experimental data by the FINUDA Collaboration. The discrepancy with the results...

J/psi and psi' production and their normal nuclear absorption in proton-nucleus collisions at 400 GeV

NA50 Collaboration
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/12/2006
Relevância na Pesquisa
45.88%
We report a new measurement of J/psi, psi' and Drell-Yan cross-sections, in the kinematical domain $-0.425

Nuclear break-up of 11Be

Lima, V.; Scarpaci, J. A.; Lacroix, D.; Blumenfeld, Y.; Bourgeois, C.; Chabot, M.; Chomaz, Ph.; Desesquelles, P.; Duflot, V.; Duprat, J.; Fallot, M.; Frascaria, N.; Grevy, S.; Guillemaud-Mueller, D.; Roussel-Chomaz, P.; Savajols, H.; Sorlin, O.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 25/09/2007
Relevância na Pesquisa
45.88%
The break-up of 11Be was studied at 41AMeV using a secondary beam of 11Be from the GANIL facility on a 48Ti target by measuring correlations between the 10Be core, the emitted neutrons and gamma rays. The nuclear break-up leading to the emission of a neutron at large angle in the laboratory frame is identified with the towing mode through its characteristic n-fragment correlation. The experimental spectra are compared with a model where the time dependent Schrodinger equation (TDSE) is solved for the neutron initially in the 11 Be. A good agreement is found between experiment and theory for the shapes of neutron experimental energies and angular distributions. The spectroscopic factor of the 2s orbital is tentatively extracted to be 0.46+-0.15. The neutron emission from the 1p and 1d orbitals is also studied.

Multihadron production dynamics exploring energy balance in hadronic to nuclear collisions

Sarkisyan, Edward K. G.; Mishra, Aditya Nath; Sahoo, Raghunath; Sakharov, Alexander S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/06/2015
Relevância na Pesquisa
45.88%
The multihadron production in nucleus-nucleus collisions and its interrelation with that in (anti)proton-proton interactions are studied by exploring the charged particle mean multiplicity collision-energy and centrality dependencies in the measurements to date. The study is performed in the framework of the recently proposed effective-energy approach which, under the proper scaling of the collision energy, combines the constituent quark picture with Landau relativistic hydrodynamics counting for the centrality-defined effective energy of participants and relating different types of collisions. Within this approach, the multiplicity energy dependence and the pseudorapidity spectra from the most central nuclear collisions are well reproduced. The study of the multiplicity centrality dependence reveals a new scaling between the measured pseudorapidity spectra and the calculations. By means of this scaling, called the energy balanced limiting fragmentation scaling, one reproduces the pseudorapidity spectra for all centralities. The scaling elucidates some differences in the multiplicity and midrapidity density centrality dependence obtained at RHIC and LHC. These findings reveal an inherent similarity in the multiplicity energy dependence from the most central collisions and centrality data. A new regime in heavy-ion collisions to occur at about a TeV energy is indicated...

Forward $D$ predictions for $p\rm Pb$ collisions, and sensitivity to cold nuclear matter effects

Gauld, Rhorry
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/08/2015
Relevância na Pesquisa
45.88%
Predictions are provided for double differential cross sections and forward-backward ratios of $D^{0}$ production in $p\rm Pb$ (forward) and $\rm{Pb}$$p$ (backward) collisions at 5.02~TeV. The effect of nuclear corrections on the ratio of differential cross sections ratios is estimated to be $\simeq$ (10-30)\% in the kinematically accessible region of LHCb, and interestingly this ratio is approximately flat with respect to $p_T(D^0)$ due to a compensation of shadowing and anti-shadowing effects arising from the input nuclear PDFs. In comparison to $J/\psi$ measurements which have already been performed with the available data, the cross section for $D^{0}$ production is expected to be two-orders of magnitude higher.; Comment: 4.5 pages + References+Appendix. Includes 4 figures and 3 tables

On the determination of anti-neutrino spectra from nuclear reactors

Huber, Patrick
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.88%
In this paper we study the effect of, well-known, higher order corrections to the allowed beta decay spectrum on the determination of anti-neutrino spectra resulting from the decays of fission fragments. In particular, we try to estimate the associated theory errors and find that induced currents like weak magnetism may ultimately limit our ability to improve the current accuracy and under certain circumstance could even largely increase the theoretical errors. We also perform a critical evaluation of the errors associated with our method to extract the anti-neutrino spectrum using synthetic beta spectra. It turns out, that a fit using only virtual beta branches with a judicious choice of the effective nuclear charge provides results with a minimal bias. We apply this method to actual data for U235, Pu239 and Pu241 and confirm, within errors, recent results, which indicate a net 3% upward shift in energy averaged anti-neutrino fluxes. However, we also find significant shape differences which can in principle be tested by high statistics anti-neutrino data samples.; Comment: 20 pages, 5 figures, 9 tables, added references, version accepted for publication in Phys. Rev. C. Corrected errors in tab. 1 and eqs. 18 and 19. Results and conclusion unchanged

On similarities of bulk observables in nuclear and particle collisions

Sarkisyan, Edward K. G.; Sakharov, Alexander S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.88%
We study the regularities in the multiparticle production data obtained from different types of collisions indicating the universality of the hadroproduction process. The similarities of such bulk variables like the charged particle mean multiplicity and the pseudorapidity density at midrapidity measured in nucleus-nucleus, (anti)proton-proton and e+e- interactions are analysed according to the dissipating energy of participants and their types. This approach shows a good agreement with the measurements in a wide range of nuclear collision energies from AGS to RHIC. The predictions up to the LHC energies are made and compared to experimental extrapolations.; Comment: 14 pages, 2 eps figures

Nuclear Modification Factor in d+Au Collisions: Onset of Suppression in the Color Glass Condensate

Kharzeev, Dmitri; Kovchegov, Yuri V.; Tuchin, Kirill
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.88%
We perform a quantitative analysis of the nuclear modification factor in deuteron--gold collisions R(dAu) within the Color Glass Condensate approach, and compare our results with the recent data from RHIC experiments. Our model leads to Cronin enhancement at mid-rapidity, while at forward rapidities it predicts strong suppression of R(dAu) at all pT due to low-x evolution. We demonstrate that our results are consistent with the data for dAu charged hadron spectra, R(dAu) and R(CP) recently reported for rapidities in the interval eta=0--3.2 by the BRAHMS experiment at RHIC. We also make a prediction for R(pA) at mid-rapidity in pA collisions at the LHC.; Comment: 8 pages, 4 figures; results for negatively charged hadrons at forward rapidities are added

Cherenkov and Fano effects at the origin of asymmetric vector mesons in nuclear media

Dremin, I. M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/05/2015
Relevância na Pesquisa
45.88%
It is argued that the experimentally observed phenomenon of asymmetric vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Cherenkov and Fano effects. The mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape in the low-mass wing of the resonance. That is explained by the positive real part of the amplitude in this wing for classic Cherenkov treatment and further detalized in quantum mechanics as the interference of direct and continuum states in Fano effect. The corresponding parameters are found from the comparison with rho-meson data and admit reasonable explanation.; Comment: 7 pages, 1 figure

Systematic study of nuclear matrix elements in neutrinoless double-beta decay with a beyond mean-field covariant density functional theory

Yao, J. M.; Song, L. S.; Hagino, K.; Ring, P.; Meng, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.88%
We report a systematic study of nuclear matrix elements (NMEs) in neutrinoless double-beta decays with a state-of-the-art beyond mean-field covariant density functional theory. The dynamic effects of particle-number and angular-momentum conservations as well as quadrupole shape fluctuations are taken into account with projections and generator coordinate method for both initial and final nuclei. The full relativistic transition operator is adopted to calculate the NMEs. The present systematic studies show that in most of the cases there is a much better agreement with the previous non-relativistic calculation based on the Gogny force than in the case of the nucleus $^{150}$Nd found in Song et al. [Phys. Rev. C 90, 054309 (2014)]. In particular, we find that the total NMEs can be well approximated by the pure axial-vector coupling term with a considerable reduction of the computational effort.; Comment: 9 pages with 7 figures and 3 tables

Fragment size correlations in finite systems - application to nuclear multifragmentation

Desesquelles, Pierre
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/09/2001
Relevância na Pesquisa
45.88%
We present a new method for the calculation of fragment size correlations in a discrete finite system in which correlations explicitly due to the finite extent of the system are suppressed. To this end, we introduce a combinatorial model, which describes the fragmentation of a finite system as a sequence of independent random emissions of fragments. The sequence is accepted when the sum of the sizes is equal to the total size. The parameters of the model, which may be used to calculate all partition probabilities, are the intrinsic probabilities associated with the fragments. Any fragment size correlation function can be built by calculating the ratio between the partition probabilities in the data sample (resulting from an experiment or from a Monte Carlo simulation) and the 'independent emission' model partition probabilities. This technique is applied to charge correlations introduced by Moretto and collaborators. It is shown that the percolation and the nuclear statistical multifragmentaion model ({\sc smm}) are almost independent emission models whereas the nuclear spinodal decomposition model ({\sc bob}) shows strong correlations corresponding to the break-up of the hot dilute nucleus into nearly equal size fragments.

Production of $e^+e^-$ Pairs Accompanied by Nuclear Dissociation in Ultra-Peripheral Heavy Ion Collision

Adams, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.88%
We present the first data on $e^+e^-$ pair production accompanied by nuclear breakup in ultra-peripheral gold-gold collisions at a center of mass energy of 200 GeV per nucleon pair. The nuclear breakup requirement selects events at small impact parameters, where higher-order corrections to the pair production cross section should be enhanced. We compare the pair kinematic distributions with two calculations: one based on the equivalent photon approximation, and the other using lowest-order quantum electrodynamics (QED); the latter includes the photon virtuality. The cross section, pair mass, rapidity and angular distributions are in good agreement with both calculations. The pair transverse momentum, $p_T$, spectrum agrees with the QED calculation, but not with the equivalent photon approach. We set limits on higher-order contributions to the cross section. The $e^+$ and $e^-$ $p_T$ spectra are similar, with no evidence for interference effects due to higher-order diagrams.; Comment: 6 pages with 3 figures Slightly modified version that will appear in Phys. Rev. C

Spin physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC)

Rakotozafindrabe, A.; Anselmino, M.; Arnaldi, R.; Brodsky, S. J.; Chambert, V.; Didelez, J. P.; Ferreiro, E. G.; Fleuret, F.; Genolini, B.; Hadjidakis, C.; Lansberg, J. P.; Lorce, C.; Rosier, P.; Schienbein, I.; Scomparin, E.; Uggerhoj, U. I.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/01/2013
Relevância na Pesquisa
45.89%
We outline the opportunities for spin physics which are offered by a next generation and multi-purpose fixed-target experiment exploiting the proton LHC beam extracted by a bent crystal. In particular, we focus on the study of single transverse spin asymetries with the polarisation of the target.; Comment: Contributed to the 20th International Spin Physics Symposium, SPIN2012, 17-22 September 2012, Dubna, Russia, 4 pages, LaTeX

Hard Probes with the STAR Experiment

Dunlop, J. C.; Collaboration, STAR
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/10/2005
Relevância na Pesquisa
45.89%
Recent results on the use of hard probes in heavy ion collisions by the STAR experiment at RHIC are reviewed. The increased statistical reach from RHIC run 4 and utilization of the full capabilities of the STAR experiment have led to a qualitative improvement in these results. Light hadrons have been identified out to transverse momenta ($p_T$) of 12 GeV/c, allowing for clear identification of the dominant processes governing particle production in different $p_T$ windows. Clean signatures of dijets have been seen even in central Au+Au collisions. Nuclear modification factors for non-photonic electrons, predominantly from the decay of heavy-flavored hadrons, have also been measured out to $p_T$ of 8 GeV/c. For $p_T > \sim 6$ GeV/c, inclusive spectra of all charged hadrons, including heavy-flavored ones, appear to be suppressed equally strongly (by a factor of four to five) in central Au+Au collisions relative to p+p collisions; interestingly enough, the probability of finding a hadron from a dijet partner is suppressed to this same level.; Comment: Proceedings for Quark Matter 2005, 10 pages, 7 figures

Heavy-flavour measurements in pp and Pb-Pb collisions with the ALICE experiment at the CERN LHC

Averbeck, Ralf; Collaboration, for the ALICE
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/02/2012
Relevância na Pesquisa
45.89%
The ALICE experiment at the CERN LHC has conducted first systematic studies of heavy-flavour hadron production in pp collisions at sqrt(s) = 7 TeV and in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV. In pp collisions the differential production cross sections of D mesons at mid-rapidity, as well as the cross sections for electrons and muons from semileptonic heavy-flavour hadron decays at mid- and forward-rapidity, respectively, have been measured. These data provide a crucial testing ground for perturbative QCD calculations in the new LHC energy regime. In Pb-Pb collisions, the nuclear modification factor R_AA(p_t) has been measured for D mesons and for leptons from heavy-flavour decays, indicating energy loss of heavy quarks in the partonic medium produced in Pb-Pb collisions at the LHC. The strong interaction of charm quarks with this medium might also generate a non-zero elliptic flow of D mesons as first studies of the azimuthal anisotropy of D^0-meson production suggest.; Comment: 14 pages, 8 figures, Conference Proceedings "LHC on the March", Protvino, Russia, November 2011

Preliminary study of kaonic deuterium X-rays by the SIDDHARTA experiment at DAFNE

Bazzi, M.; Beer, G.; Berucci, C.; Bombelli, L.; Bragadireanu, A. M.; Cargnelli, M.; Curceanu, C.; d'Uffizi, A.; Fiorini, C.; Frizzi, T.; Ghio, F.; Guaraldo, C.; Hayano, R.; Iliescu, M.; Ishiwatari, T.; Iwasaki, M.; Kienle, P.; Sandri, P. Levi; Longoni, A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.89%
The study of the KbarN system at very low energies plays a key role for the understanding of the strong interaction between hadrons in the strangeness sector. At the DAFNE electron-positron collider of Laboratori Nazionali di Frascati we studied kaonic atoms with Z=1 and Z=2, taking advantage of the low-energy charged kaons from Phi-mesons decaying nearly at rest. The SIDDHARTA experiment used X-ray spectroscopy of the kaonic atoms to determine the transition yields and the strong interaction induced shift and width of the lowest experimentally accessible level (1s for H and D and 2p for He). Shift and width are connected to the real and imaginary part of the scattering length. To disentangle the isospin dependent scattering lengths of the antikaon-nucleon interaction, measurements of Kp and of Kd are needed. We report here on an exploratory deuterium measurement, from which a limit for the yield of the K-series transitions was derived: Y(K_tot)<0.0143 and Y(K_alpha)<0.0039 (CL 90%). Also, the upcoming SIDDHARTA-2 kaonic deuterium experiment is introduced.; Comment: Accepted by Nuclear Physics A