Related papers: Mixing of partial waves near $B^* \bar B^*$ thresh…
We present microcanonical ensemble calculations of particle number fluctuations in the ideal pion gas approaching Bose-Einstein condensation. In the samples of events with a fixed number of all pions, $N_{\pi}$, one may observe a prominent…
We consider non-relativistic "dark" particles interacting through gauge boson exchange. At finite temperature, gauge exchange is modified in many ways: virtual corrections lead to Debye screening; real corrections amount to frequent…
We investigate a contribution of the $d$ wave to the cross section of $e^+e^-$ annihilation to the pair of charged leptons or nucleons close to threshold of the process. In contrast to the point of view accepted in literature, due to the…
We develop an approach for calculating matrix elements of meson exchange currents between 3N basis states in (jJ)-coupling and a 3N bound state. The contribution generated by $\pi$- and $\rho$-exchange are included in the consideration. The…
Using precise data from the BESIII collaboration, we obtained compelling evidence of a subthreshold pole in the $e^+ e^-\rightarrow D_s^+ D_s^-$ process with mass of (3896$^{+13}_{-22}$)~MeV. The latter suggests the identification of this…
We consider a loop mixing of two fermion fields of opposite parities whereas the parity is conserved in a Lagrangian. Such kind of mixing is specific for fermions and has no analogy in boson case. Possible applications of this effect may be…
In e^+e^- annihilation at \sqrt{s}=10.6 GeV Belle Collaboration found, that J/psi mesons are predominantly produced in association with an extra \bar{c}c pair. The possible mechanisms of J/psi production are discussed and the probability of…
Cross sections of the e+e- annihilation into one photon plus two vector mesons, such as J/psi rho, J/psi phi, and rho phi at the center of mass energy \sqrt{s}=10.58GeV are calculated. These shed light on the measurement of the e+e-…
The cross section of the pd -> 3He pi+ pi - reaction has been measured at the MOMO facility in a kinematically complete experiment at a c. m. excess energy of Q = 70 MeV. The energy and angular distributions show that the reaction is…
Pion exchange is the central ingredient to nucleon-nucleon interactions used in nuclear structure calculations, and one pion exchange (OPE) enters at leading order in chiral effective field theory. In the $^{2S+1}L_J={^1S_0}$ partial wave,…
We investigate the processes $e^+e^-$ annihilating to $J/\psi\pi\pi$, $\psi^\prime\pi\pi$ and $h_c\pi\pi$. The coupled-channel effects induced by the couplings between the widely accepted $D$-wave charmonium $\psi(4160)$ and $D_1D$,…
Based on $e^+e^-$ annihilation data samples collected with the BESIII detector at the BEPCII collider at 13 center of mass energies from 4.008 to 4.600 GeV, measurements of the Born cross section of $e^{+}e^{-}\rightarrow p \bar{p} \pi^{0}$…
The scalar-isoscalar pi-pi phase shifts are calculated in the pi-pi energy range from 600 MeV to 1600 MeV. We use results of the CERN-Cracow-Munich collaboration for the reaction pi^- p --> pi^+ pi^- n on a transversely polarized target at…
We study, at leading order in the large number of colours expansion and within the Resonance Chiral Theory framework, the odd-intrinsic-parity $e^+ e^- \rightarrow \pi^+ \pi^- (\pi^0, \eta)$ cross-sections in the energy regime populated by…
The experimental isoscalar $\pi\pi\to\pi\pi$ S-wave amplitude squared below 1.75 GeV is characterized by a very broad structure $f_0(400-1200)$ with two narrow dips due to its destructive interference with the $f_0(980)$ and $f_0(1500)$.…
At very high energies, pair production ($\gamma\to e^+e^-$) exhibits many interesting features. The momentum transfer from the target is very small, so the reaction probes the macroscopic properties of the target, rather than individual…
The fragmentation of an unpolarized quark into a transversely polarized spin-1/2 particle is studied in the framework of a simple model. Special attention is payed to the gluon exchange which is incorporated in the gauge link of the…
We discuss the puzzling experimental results on baryon-antibaryon production in e+e- annihilation close to the threshold, in particular the fact that sigma(e+e- --> nbar n) is somewhat greater than sigma(e+e- --> pbar p). We discuss an…
Model independent formulae are derived for the beam analyzing power $A_y$ and beam to meson spin transfers in $pp \to pp \omega$ taking into consideration all the six threshold partial wave amplitudes covering the $Ss, Sp$ and $Ps$…
We calculate the cross sections for dissociation of $J/\psi$ by pions and $\rho$-mesons within the framework of a meson exchange model. We find that these cross sections are small at center-of-mass energies less than 1 GeV above threshold,…