scholarly journals MEASUREMENT OF DIFFERENTIAL CROSS SECTIONS OF p(e, e′π+)n FOR HIGH-LYING RESONANCES AT Q2 < 5 GeV2

2014 ◽  
Vol 26 ◽  
pp. 1460102
Author(s):  
◽  
KIJUN PARK

The exclusive electroproduction process ep → e′nπ+ was measured in the range of the invariant mass for nπ+ system 1.6 GeV ≤ W ≤ 2.0 GeV, and the photon virtuality 1.8 GeV2 ≤ Q2 ≤ 4.0 GeV2 using CLAS. For the first time, these kinematics are probed in exclusive π+ production from the protons with nearly full coverage in the azimuthal and polar angles of the nπ+ center-of-mass system. In this experiment, approximately 39,000 differential cross-section data points were measured. In this conference proceeding, preliminary results of our latest analysis work are presented on differential cross sections and structure functions as well as Legendre Moments.

2014 ◽  
Vol 26 ◽  
pp. 1460101 ◽  
Author(s):  
◽  
PAUL MATTIONE

Preliminary measurements of the differential cross sections of the γn → K*(892)0Λ and γn → K+Σ*(1385)- reactions are shown using data from the Jefferson Lab Hall B CLAS g13 experiment. No experimental cross section data have yet been published on the γn → K*(892)0Λ reaction, and the only published cross section data on the γn → K+Σ*(1385)- reaction are at forward angles, where t-channel K+ and K*+ exchanges are predicted to dominate. These data can be used to contribute to the search for the "missing" N* resonances, some of which are predicted to have non-negligible couplings to the excited strangeness channels.


2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

Abstract Measurements of the differential cross sections of Z + jets and γ + jets production, and their ratio, are presented as a function of the boson transverse momentum. Measurements are also presented of the angular distribution between the Z boson and the closest jet. The analysis is based on pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb−1 recorded by the CMS experiment at the LHC. The results, corrected for detector effects, are compared with various theoretical predictions. In general, the predictions at higher orders in perturbation theory show better agreement with the measurements. This work provides the first measurement of the ratio of the differential cross sections of Z + jets and γ + jets production at 13 TeV, as well as the first direct measurement of Z bosons emitted collinearly with a jet.


2019 ◽  
Vol 15 (32) ◽  
pp. 77-91
Author(s):  
Maha Taha Idrees

The pre - equilibrium and equilibrium double differential crosssections are calculated at different energies using Kalbach Systematicapproach in terms of Exciton model with Feshbach, Kerman andKoonin (FKK) statistical theory. The angular distribution of nucleonsand light nuclei on 27Al target nuclei, at emission energy in the centerof mass system, are considered, using the Multistep Compound(MSC) and Multistep Direct (MSD) reactions. The two-componentexciton model with different corrections have been implemented incalculating the particle-hole state density towards calculating thetransition rates of the possible reactions and follow up the calculationthe differential cross-sections, that include MSC and MSD models.The finite well depth, isospin, shell effects, Pauli effect, chargeeffect, pairing, surface, angular and linear momentum distributionscorrections are considered in this work. The nucleons (n and p) andlight nuclei (2D and 3T) have been employed as projectiles at thetarget 27Al nuclei and at different incident energies (4MeV, 14 MeVand 14.8MeV). The results have been compared with the availableexperimental and theoretical published work. The comparisons showan acceptable agreement with the TALAYS code (Tendel 2014) forthe reactions: 27Al (n, n) 27Al, 27Al (p, n) 63Zn, 27Al (p, D) 62Cu, 27Al(p, p) 63Cu and 27Al (p, 4He)60Ni and at different emission energiesand angles.


2020 ◽  
Vol 29 (06) ◽  
pp. 2050030
Author(s):  
A. Vinayak ◽  
M. M. Hosamani ◽  
P. N. Patil ◽  
N. M. Badiger

The spectroscopic factor (SF) of doubly-magic nuclei, neutron shell closed and neutron-rich nuclei has been determined through ([Formula: see text], [Formula: see text]) reaction in the projectile energy range from 3 to 26[Formula: see text]MeV. The theoretical angular differential cross-sections of ([Formula: see text], [Formula: see text] reactions in scattering center-of-mass angles from [Formula: see text] to [Formula: see text] have been calculated using FRESCO and NRV-DWUCK5 codes. By comparing the theoretical angular differential cross-sections with available experimental angular differential cross-sections, the values of SF have been determined. The exponential increase of SF as a function of neutron separation energy normalized by spin of the recoil nuclei has been shown for the first time for doubly-magic nuclei. The similar type of trend has also been observed for neutron-rich as well as neutron shell closed nuclei as a function of neutron separation energy normalized by asymmetric factor of recoil nucleus. More experimental data are required to verify the trend predicted by this investigation.


1988 ◽  
Vol 66 (1) ◽  
pp. 82-85
Author(s):  
K. S. Baliyan ◽  
M. K. Srivastava

The recent triple differential cross-section data of Jung for the ionization of helium in the coplanar asymmetric geometry at 250 eV incident electron energy is analyzed within the framework of the second Born (B2) and modified Glauber (MG) approximations. At this energy B2 and MG results, although better than those obtained by using the first Born and Glauber approximations, do not lead to a satisfactory description of the experimental data in all the kinematic situations considered here.


2021 ◽  
Author(s):  
M. Salimi ◽  
O. Kakuee ◽  
S. F. Masoudi ◽  
H. R. kheiri ◽  
E. Briand ◽  
...  

Abstract The cross-sections of deuteron-induced nuclear reactions suitable for ion beam analysis, measured in different laboratories, are often significantly different. In the present work, differential cross-sections of 27 Al(d,p) and 27 Al(d,α) reactions were measured, and the cross sections benchmarked with thick target spectra obtained from pure aluminium for the first time in two independent laboratories. The 27 Al(d,p) and (d,alpha) differential cross-sections were measured between 1.4 and 2 MeV at scattering angles of 165°, 150°, and 135° in the VDGT laboratory in Tehran (Iran), and the same measurements for detector angle of 150° were repeated from scratch, including target making, with independent equipment on the SAFIR platform at INSP in Paris (France). The results of these two measurements at 150° are in good agreement, and for the first time a fitted function is proposed to describe the Al-cross sections for which no suitable theoretical expression exists. The obtained differential cross-sections were validated through benchmarking, by fitting with SIMNRA deuteron-induced particle spectra obtained from a high purity bulk Al target at both labs for deuteron incident energies between 1.6 and 2 MeV. The thick target spectra are well-reproduced. The evaluated and benchmarked cross sections have been uploaded to the ion beam analysis nuclear data library database (www-nds.iaea.org/ibandl/).


1969 ◽  
Vol 47 (1) ◽  
pp. 113-115 ◽  
Author(s):  
Mark W. Kermode

The D-wave phase shifts for α−α scattering at low energies are obtained from (i) new analyses of the differential cross sections and (ii) the effects of vacuum polarization. The results are −0.4° (−0.4°), −0.2° (−0.4°), +0.2° (−0.4°), −0.2° (−0.2°), and 0.3° (0.2°) for the center-of-mass energies 0.3, 0.425, 0.5, 0.75, and 1.0 MeV, respectively. It is felt that these results are significant.


2005 ◽  
Vol 20 (08n09) ◽  
pp. 1822-1825
Author(s):  
◽  
S. PRAKHOV ◽  
A. STAROSTIN

Pion charge-exchange (π-p→π0n) differential cross sections are one of the basic sources of information on neutral pion-nucleon resonances. We present new, high statistics, high quality charge-exchange differential cross-section data obtained in the incident π- momentum range 650–750 MeV/c. The total uncertainty of the measurements is 6% or less. 648 new data points were obtained using the Crystal Ball multiphoton spectrometer covering 94% of the full solid angle. Our data show deviations from the results of the partial–wave analysis for some momenta, in particular at very backward angles. We also report on a search for the cusp effect in π-p→π0n at the opening of the π-p→ηn channel.


2005 ◽  
Vol 20 (02n03) ◽  
pp. 643-645 ◽  
Author(s):  
H.-H. ADAM ◽  
A. KHOUKAZ ◽  
N. LANG ◽  
T. LISTER ◽  
R. SANTO ◽  
...  

Measurements on the η meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY (Jülich). Here we present preliminary results on total and differential cross sections for the pd→3 He η reaction at five excess energies between Q=5.1 and Q=40.6 MeV. The obtained angular distributions for the emitted η mesons in the center of mass system expose a transition from an almost isotropic emission to a highly anisotropic distribution. The extracted total cross sections support a strong η-3 He final state interaction and will be compared with model predictions.


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