η PHOTO-PRODUCTION ON THE DEUTERON AT LNS, TOHOKU UNIVERSITY

2010 ◽  
Vol 19 (12) ◽  
pp. 2393-2399 ◽  
Author(s):  
T. Ishikawa
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Systematic Uncertainty ◽  
Cross Sections ◽  
Energy Region ◽  
Solid Angle ◽  
Total Cross Sections ◽  
Nuclear Science ◽  
Electro Magnetic ◽  
Photo Production

The differential and total cross sections were measured for the γp → ηp and γd → ηpn reactions at Eγ ≤ 1150 MeV by using an electro-magnetic (EM) calorimeter SCISSORS II at the Laboratory of Nuclear Science (LNS), Tohoku University. The total cross section on the deuteron shows a bump around Eγ = 1 GeV , while no bump is observed in the same energy region of that on the proton. This bump is attributed to be a nucleon resonance excited from the neutron, and it is a candidate of anti-decuplet penta-quark baryons with hidden strangeness. It was difficult, however, to detect all the γ's coming from η decay since the solid angle of SCISSORS II was only 12.6% in total. Statistics of the detected η produced events is poor and systematic uncertainty of the obtained cross section is not small due to low acceptance. A new EM calorimeter complex called FOREST with a solid angle of about 4π sr has been constructed. The spin and parity of the relevant resonance are expected to be determined by the experiments with FOREST.

DOUBLE PION PHOTOPRODUCTION EXPERIMENT AT LNS–TOHOKU

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2313-2316 ◽  
Author(s):  
◽  
H. KANDA ◽  
N. CHIGA ◽  
Y. FUJII ◽  
K. FUTATSUKAWA ◽  
...  
Keyword(s):  
Total Cross Section ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Pion Photoproduction ◽  
Total Cross Sections ◽  
Free Proton ◽  
Double Pion ◽  
The Cross

The total cross sections for the π+π− photoproduction on the deuteron were measured in an energy range of 0.8 to 1.1 GeV. The obtained total cross section for the quasi-free π+π− photoproduction on the deuteron was about 60 % of those on the free proton. The cross section for Δ++Δ− photoproduction was derived from the non-quasi-free π+π− photoproduction events. It was smaller than the previous data.

Pion-nucleon resonances and their effect upon π ± p total cross sections

1966 ◽  
Vol 289 (1419) ◽  
pp. 521-530 ◽  
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Recent Experiment ◽  
Isotopic Spin ◽  
Spin States ◽  
Total Cross Sections ◽  
Nucleon Resonances ◽  
Pion Nucleon

Precise measurements of the total cross sections of positive and negative π mesons on hydrogen have revealed the presence of structure or enhancements in these cross sections at various momenta up to 3 GeV/ c . The present paper discusses measurements of this type and in particular, a recent experiment to search for structure in the region 3 to 7 GeV/ c , where previous experiments have shown that, if structure were present, it was likely to reveal itself as an amplitude in the total cross section of 1 mb or less. The recent measurements indicate four regions of structure, two in each of the isotopic spin states 3/2 and 1/2. The possible relation of these regions of structure to the formation of pion-nucleon resonances is discussed.

THE SPIN CONTRIBUTION TO THE pp-TOTAL CROSS-SECTION AT HIGH ENERGY

1998 ◽  
Vol 13 (09) ◽  
pp. 1515-1522 ◽  
Author(s):  
E. A. ANDREEVA ◽  
M. N. STRIKHANOV ◽  
S. B. NURUSHEV
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
High Energy ◽  
Spin Projection ◽  
Total Cross Sections ◽  
Spin Effects ◽  
Dependent Term ◽  
Spin Interactions ◽  
200 Gev

The experimental data on the pp-total cross-sections including the spin-dependent parts are analyzed with the goal to determine the contribution of spin interactions at high energies. Based on the Regge model with cuts, the energy dependencies of such contributions are estimated for two spin-dependent terms: (1) the total spin dependent term, σ1 and (2) the spin projection dependent term, σ2. The estimates show that their contributions to the unpolarized total cross section, σ0, decrease with energy from several % around 2 GeV/c to 10-2% around 200 GeV/c. The assumption σ1= -σ2 does not seem to be correct, while the hypothesis 3 σ1=-σ2 is more preferable, especially in the measured energy interval 2-6 GeV. There is a clear indication that the spin effects are sensitive to the pomeron intercept at - t=0 (GeV/c)2. In order to pin down such effects the spin dependent total cross-sections must be measured with precisions better than 10 μb at 200 GeV/c.

Total cross sections and isomeric cross-section ratios for (n, 2n) reactions in the energy region 12–18 MeV

1970 ◽  
Vol 157 (2) ◽  
pp. 481-496 ◽  
Author(s):  
M. Bormann ◽  
H.H. Bissem ◽  
E. Magiera ◽  
R. Warnemünde
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Energy Region ◽  
Total Cross Sections

scholarly journals Effect of Rapidly Rising Proton?Proton Total Cross Sections on Idealized Extensive Air Showers

1972 ◽  
Vol 25 (6) ◽  
pp. 679
Author(s):  
JA Campbell
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Strong Interaction ◽  
Extensive Air Showers ◽  
Proton Scattering ◽  
Air Showers ◽  
Proton Proton ◽  
Total Cross Sections ◽  
First Time

A simulation of extensive air showers above 1013 eV in which proton?proton scattering takes place partly through a medium-strong interaction is reported. In previous papers the simulation has been shown to be in fair agreement with observational data. The present version includes for the first time the assumption that the total cross section for proton-proton scattering increases with energy, as concluded in a recent paper by Yodh, Pal, and Trefil. The effect of the assumption is to make a noticeably better agreement between the simulation and the data.

scholarly journals AN UPDATED ANALYSIS ON THE RISE OF THE HADRONIC TOTAL CROSS-SECTION AT THE LHC ENERGY REGION

2013 ◽  
Vol 28 (20) ◽  
pp. 1350099 ◽  
Author(s):  
M. J. MENON ◽  
P. V. R. G. SILVA
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Particle Physics ◽  
Energy Region ◽  
High Energy ◽  
Critical Discussion ◽  
Elastic Cross Section ◽  
Amplitude Analysis ◽  
8 Tev

A forward amplitude analysis on pp and [Formula: see text] elastic scattering above 5 GeV is presented. The dataset includes the recent high-precision TOTEM measurements of the pp total and elastic (integrated) cross-sections at 7 TeV and 8 TeV. Following previous works, the leading high-energy contribution for the total cross-section (σ tot ) is parametrized as ln γ(s/sh), where γ and sh are free real fit parameters. Singly-subtracted derivative dispersion relations are used to connect σ tot and the rho parameter (ρ) in an analytical way. Different fit procedures are considered, including individual fits to σ tot data, global fits to σ tot and ρ data, constrained and unconstrained data reductions. The results favor a rise of the σ tot faster than the log-squared bound by Froissart and Martin at the LHC energy region. The parametrization for σ tot is extended to fit the elastic cross-section (σ el ) data with satisfactory results. The analysis indicates an asymptotic ratio σ el /σ tot consistent with 1/3 (as already obtained in a previous work). A critical discussion on the correlation, practical role and physical implications of the parameters γ and sh is presented. The discussion confronts the 2002 prediction of σ tot by the COMPETE Collaboration and the recent result by the Particle Data Group (2012 edition of the Review of Particle Physics). Some conjectures on possible implications of a fast rise of the proton–proton total cross-section at the highest energies are also presented.

scholarly journals THE POMERON AND ODDERON IN ELASTIC, INELASTIC AND TOTAL CROSS-SECTIONS AT THE LHC

2011 ◽  
Vol 26 (27n28) ◽  
pp. 4755-4771 ◽  
Author(s):  
L. L. JENKOVSZKY ◽  
A. I. LENGYEL ◽  
D. I. LONTKOVSKYI
Keyword(s):  
Simple Model ◽  
Cross Section ◽  
Cross Sections ◽  
Energy Region ◽  
Scattering Amplitude ◽  
Total Cross Sections ◽  
Regge Trajectories ◽  
Relative Contribution ◽  
Main Emphasis

A simple model for elastic diffractive hadron scattering, reproducing the dip-bump structure is used to analyze pp and [Formula: see text] scattering. The main emphasis is on the delicate and nontrivial dynamics in the dip-bump region, near t = -1 GeV 2. The simplicity of the model and the expected smallness of the absorption corrections enables one the control of various contributions to the scattering amplitude, in particular the interplay between the C-even and C-odd components of the amplitude, as well as their relative contribution, changing with s and t. The role of the nonlinearity of the Regge trajectories is scrutinized. The ratio of the real to imaginary parts of the forward amplitude, the ratio of elastic to total cross-sections and the inelastic cross-section are calculated. Predictions for the LHC energy region, where most of the existing models will be either confirmed or ruled out, are presented.

INCLUSIVE REACTIONS AND TOTAL CROSS SECTIONS WITH POLARIZED INITIAL STATES

1986 ◽  
Vol 01 (01) ◽  
pp. 211-225 ◽  
Author(s):  
GARY R. GOLDSTEIN ◽  
MICHAEL J. MORAVCSIK
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Final State ◽  
Total Cross Sections ◽  
Initial States

Total cross section measurements and the type of inclusive reactions in which no final-state polarizations are measured are discussed. The numbers and kinds of independent non-zero experiments are given and related to the exclusive reaction amplitudes. Only a well-specified and limited type of bilinear product of exclusive reaction amplitudes enter the picture. Certain classes of theories imply certain simple relationships among the observables. The main results of the investigation are summarized in Sec. 5.

ELASTIC AND INELASTIC SCATTERING OF POSITRONS BY POTASSIUM ATOMS

2007 ◽  
Vol 21 (10) ◽  
pp. 625-637 ◽  
Author(s):  
SALAH YASEEN EL-BAKRY
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Positronium Formation ◽  
Electron Model ◽  
Static Approximation ◽  
Total Cross Sections ◽  
Energy Formula ◽  
The One ◽  
Good Agreement

The investigations of the elastic and inelastic collisions of positrons with potassium atoms, K (1s2, 2s2, 2p6, 3s2, 3p6, 4s), are presented. The potassium target atoms are described using Clementi–Roetti wavefunctions within the framework of the one-valence-electron model. The total cross-sections which correspond to eight partial cross-sections are calculated at 34 values of the incident energy [Formula: see text] using the coupled-static approximation. The resulting total elastic, ground- and excited-positronium formation cross-sections are compared with experimental results and those calculated by other authors. In the vicinity of 6 eV, and consistent with the measurements of Parikh et al.,2 our total cross-section displays a pronounced peak. We support the conclusion of McAlinden et al.15 and Hewitt et al.14 that above about 4 eV, positronium formation is mainly into excited states. Good agreement is obtained with the total cross-section measurements of Kwan et al.1 and Parikh et al.2 Positronium formation is not important above about 50 eV.

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