scholarly journals Interaction of real and virtual NN̅ pairs in J/ψ decays

2018 ◽  
Vol 181 ◽  
pp. 01020
Author(s):  
Alexander Milstein ◽  
Sergey Salnikov

The differential decay rates of the processes J/ψ→pp̅π0, J/ψ→pp̅η, J/ψ→pp̅ω, J/ψ→pp̅ρ, and J/ψ→pp̅γ close to the pp̅ threshold are calculated with the help of the NN̅ optical potential. We use the potential which has been suggested to fit the cross sections of NN̅ scattering together with all other NN̅ experimental data available. The pp̅ nvariant mass spectra of J/ψ decays are in agreement with the available experimental data. The anisotropy of the angular distributions of the decays J/ψ→pp̅π0(η), which appears due to the tensor forces in the NN̅ interaction, is predicted close to the pp̅ threshold. This anisotropy is large enough to be investigated experimentally. Such measurements would allow one to check the accuracy of the model of NN̅ interaction, is predicted close to the pp̅ threshold. This anisotropy is large enough to be investigated experimentally. Such measurements would allow one to check the accuracy of the model of NN̅ interaction. Using our potential and the Green’s function approach we also describe the peak in the η′ π+ π- invariant mass spectrum in the decay J/ψ → γ η′ π+ π- in the energy region near the NN̅ threshold.

2004 ◽  
Vol 19 (31) ◽  
pp. 5493-5500 ◽  
Author(s):  
MICHAEL TROTT

Recent advances in improving extractions of |Vcb| and mb from spectra of semileptonic inclusive B decay are reported. Results of a general moment analysis of the lepton energy spectrum and the hadronic invariant mass spectrum are summarized. The calculation of the general [Formula: see text] structure functions for semileptonic B decay is reported, which has allowed the calculation of the [Formula: see text] terms for the hadronic invariant mass moments to be carried out. Recent theoretical advances and improvements in experimental data has allowed extractions of the CKM matrix element |Vcb| to improve to the 2% level.


2019 ◽  
Vol 218 ◽  
pp. 04003
Author(s):  
Alexandr Milstein

The pp¯invariant mass spectra in the processes e+e−→ pp¯, e+e−→ nn¯, J/ψ → pp¯ω, J/ψ → pp¯ρ, and J/ψ → pp¯γ close to the pp¯is discussed. The optical potentials for NN¯pair in the superposition of S and D waves (due to tensor forces) at spin unity of the pair, as well as for NN¯pair in the S wave at spin zero of the pair, are proposed. The parameters of the potentials are obtained by fitting the cross sections of NN¯scattering together with the pp¯invariant mass spectra in e+e−→ pp¯annihilation and J/ψ decays. Good agreement with the available experimental data is achieved. Using our potential and the Green’s function approach we also describe the cross section of e+ e−→ 6π and the η’π+ π− invariant mass spectrum in the decay J/ψ → γη’π+π− in the energy region near the NN¯threshold.


2010 ◽  
Vol 25 (32) ◽  
pp. 5963-5972 ◽  
Author(s):  
C. Z. YUAN ◽  
X. H. MO ◽  
P. WANG

Multiple solutions exist in many experimental situations where several interfering amplitudes are summed to fit experimentally measured distributions, such as cross sections, mass spectra, and/or angular distributions. We show a few examples where multiple solutions are found, but only one solution is reported in publications. Since there is no standard rule for choosing one among the solutions as the physics one, we propose a simple rule that agrees with what has been adopted in previous literature: the solution corresponding to the minimal magnitudes of the amplitudes must be the physical solution. We suggest testing this rule in future analyses.


2012 ◽  
Vol 27 (01) ◽  
pp. 1230002
Author(s):  
JADRANKA SEKARIC

The recent claim by the CDF Collaboration of a possible anomalous dijet resonance in their data required experimental verification from other hadron collider experiments. We present a study of the dijet invariant mass spectrum in events with two jets produced in association with a W→ℓν boson at the DØ experiment. We investigate the dijet mass range between 110 GeV /c2 and 170 GeV /c2 and find no evidence for any resonant dijet production.


2018 ◽  
Vol 120 (20) ◽  
Author(s):  
M. Aaboud ◽  
G. Aad ◽  
B. Abbott ◽  
O. Abdinov ◽  
B. Abeloos ◽  
...  

1997 ◽  
Vol 56 (6) ◽  
pp. R2920-R2923 ◽  
Author(s):  
R. Holzmann ◽  
M. Appenheimer ◽  
R. Averbeck ◽  
Y. Charbonnier ◽  
H. Delagrange ◽  
...  

2018 ◽  
Vol 64 (5) ◽  
pp. 498
Author(s):  
Hocine Aouchiche

Differential and integral cross sections for elastic scattering of electron by NH3 molecule are investigated for the energy ranging from 10 eV to 20 keV.  The calculations are carried out in the framework of partial wave formalism describing the target molecule by means of one center molecular Hartree-Fock functions.  A spherical complex optical potential used includes a static part – obtained here numerically from quantum calculation – and fine effects like correlation, polarization and exchange potentials. The results obtained in this model point out clearly the role played by the exchange and the correlation-polarization contributions in particular at lower scattering angles and lower incident energies. Both differential and integral cross sections obtained are compared with a large set of experimental data available in the literature and well agreement is found throughout the scattering angles and whole energy range investigated here.


2002 ◽  
Vol 11 (05) ◽  
pp. 425-436 ◽  
Author(s):  
M. Y. H. FARAG ◽  
M. Y. M. HASSAN

The relativistic description of the proton-nucleus elastic scattering can be considered within the framework of a relativistic optical potential model. The elastic scattering of proton with the nuclei 12 C , 16 O , 20 Ne , and 24 Mg at 800 MeV and 1.04 GeV are studied for relativistic and nonrelativistic treatments. The real optical potentials and the differential cross sections of these reactions are calculated. The obtained results are compared with the corresponding results obtained from the calculation depending on the Woods–Saxon optical potential which were adjusted to fit the experimental data. The present results are in good agreement with the experimental data.


Sign in / Sign up

Export Citation Format

Share Document