scholarly journals Analysis of the image of pion-emitting sources in the source center-of-mass frame

2017 ◽  
Vol 53 (8) ◽  
Author(s):  
Yanyu Ren ◽  
Qichun Feng ◽  
Weining Zhang ◽  
Lei Huo ◽  
Jingbo Zhang ◽  
...  
Keyword(s):  
2010 ◽  
Vol 09 (05) ◽  
pp. 935-943 ◽  
Author(s):  
PENG SONG ◽  
YONG-HUA ZHU ◽  
JIAN-YONG LIU ◽  
FENG-CAI MA

The stereodynamics of the title reaction on the ground electronic state X2A' potential energy surface (PES)1 has been studied using the quasiclassical trajectory (QCT) method. The commonly used polarization-dependent differential cross-sections (PDDCSs) of the product and the angular momentum alignment distribution, P(θr) and P(Φr), are generated in the center-of-mass frame using QCT method to gain insight of the alignment and orientation of the product molecules. Influence of collision energy on the stereodynamics is shown and discussed. The results reveal that the distribution of P(θr) and P(Φr) is sensitive to collision energy. The PDDCSs exhibit different collision energy dependency relationship at low and high collision energy ranges.


2021 ◽  
Vol 84 (1) ◽  
pp. 59-62
Author(s):  
M. N. Achasov ◽  
A. Yu. Barnyakov ◽  
M. Yu. Barnyakov ◽  
K. I. Beloborodov ◽  
A. V. Berdyugin ◽  
...  

2001 ◽  
Vol 16 (22) ◽  
pp. 3745-3753 ◽  
Author(s):  
JUN-CHEN SU ◽  
JIAN-XING CHEN

It is pointed out that the retardation terms given in the original Fermi–Breit potential vanish in the center-of-mass frame. The retarded one-gluon exchange potential is rederived in this paper from the three-dimensional one-gluon exchange kernel which appears in the exact three-dimensional relativistic equation for quark–antiquark bound states. The retardation part of the potential given in the approximation of order p2/m2 is shown to be different from those derived in the previous literature. This part is off-shell and no longer vanishes in the center-of-mass frame.


2013 ◽  
Vol 28 (18) ◽  
pp. 1350081
Author(s):  
JUN-QUAN TAO ◽  
YU-QIAO SHEN ◽  
JIA-WEI FAN ◽  
HONG XIAO ◽  
GUO-MING CHEN ◽  
...  

We calculate the destructive interference factors between the Higgs decay H→γγ produced in gluon-fusion and the Standard Model (SM) continuum gg→γγ process, as a function of the scattering angle in the center-of-mass frame of the final two photons. The interference factors are studied with the selections based on the acceptance criteria of the ATLAS and CMS H→γγ searches at the LHC. The result shows that the destructive interference is only at an order of 2.5% for the SM Higgs analysis at the LHC. The factors are almost the same for the same Higgs mass hypothesis but with different proton–proton collisions at [Formula: see text], 8 TeV, 13 TeV and 14 TeV. The destructive interference is far below the present uncertainty on the total cross-section prediction of Higgs, which is about 15% used at the LHC. A destructive interference factor of -2.5% is suggested to be used in the H→γγ analysis at the LHC, due to the effect from the interference for this decay channel.


2016 ◽  
Vol 31 (04) ◽  
pp. 1650029 ◽  
Author(s):  
O. B. Zaslavskii

We consider collision of two particles in rotating spacetimes without horizons. If the metric coefficient responsible for rotation of spacetime is big enough, the energy of collisions in the center of mass frame can be as large as one likes. This can happen in the ergoregion only. The results are model-independent and apply both to relativistic stars and wormholes.


2019 ◽  
Vol 34 (19) ◽  
pp. 1950150 ◽  
Author(s):  
Muhammad Ajaz ◽  
Irfan Khan ◽  
M. K. Suleymanov

The transverse momentum distribution of the differential production cross-sections of heavy flavored charm hadrons [Formula: see text], [Formula: see text] in pp collisions at 7 TeV are simulated. Predictions of DPMJETIII.17-1, HIJING1.383 and Sibyll2.3c are compared to the differential cross-section measurements of the LHCb experimental data presented in the region of [Formula: see text] and [Formula: see text], where the pp center of mass frame is used to measure the transverse momentum and rapidity. The models reproduce only some regions of [Formula: see text] and/or bins of [Formula: see text] but none of them predict completely all the [Formula: see text] bins over the entire [Formula: see text] range.


2014 ◽  
Vol 29 (29) ◽  
pp. 1450151
Author(s):  
O. B. Zaslavskii

We consider collision of two particles in the axially symmetric black hole metric in the magnetic field. If the value of the angular momentum |L| of one particles grows unbound (but its Killing energy remains fixed) one can achieve unbound energy in the center-of-mass frame E c.m. In the absence of the magnetic field, collision of this kind is known to happen in the ergoregion. However, if the magnetic field strength B is also large, with the ratio |L|/B being finite, large E c.m. can be achieved even far from a black hole, in the almost flat region. Such an effect also occurs in the metric of a rotating star.


2011 ◽  
Vol 20 (04) ◽  
pp. 1034-1037
Author(s):  
P. PAPKA ◽  
F. NEMULODI ◽  
R. A. BARK ◽  
N. Y. KHESWA ◽  
E. A. LAWRIE ◽  
...  

A complete kinematics measurement was performed using the 6 Li (3 He ,t) charge exchange reaction to populate 6 Be at Elab = 50 MeV . Decay mode of the ground and first excited states were studied through the analysis of the energy and angular distributions of the break-up particles in the 6 Be center of mass frame. Two-body decay is observed above the first excited state but not firmly assigned to a 6 Be resonant state. Experimental challenges regarding the identification of true 6 Be events in the excitation energy region 5 < Ex < 20 MeV are discussed.


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