Related papers: Subthreshold poles in electron-positron annihilati…
The status of the analysis of the electron/positron annihilation radiation performed by INTEGRAL/SPI in the 4th GALACTIC QUADRANT is reported. We use data from the first two Galactic Center Deep Exposures (GCDE) and from the Galactic Plane…
Fragmentation of ground state ortho Positronium (Ps) in collision with Li ion (Li+) is studied in the framework of post collisional Coulomb distorted eikonal approximation (CDEA) for the target elastic case . The present model takes account…
A threshold singularity in a heavier meson channel, e.g. $D^* {\bar D}^*$, generally reflects in the amplitudes of $e^+e^-$ annihilation into lighter meson pairs, such as $D^* {\bar D}$, $D {\bar D}$, and $D_s {\bar D}_s$, due to the…
We perform the first global and unitary analysis of $e^+e^-\to b\bar{b}$ cross sections. We analyze exclusive cross sections in the $B\bar{B}$, $B^* \bar{B}(+c.c.)$, $B^*\bar{B}^*$, $B_s^*\bar{B}_s^*$, $\Upsilon(nS)\pi^+\pi^-$ and…
Studies based on imaging the annihilation of the electron (e$^{-}$) and its antiparticle positron (e$^{+}$) open up several interesting applications in nuclear medicine and fundamental research. The annihilation process involves both the…
We compute the next-to-next-to-leading order (NNLO) QCD corrections to the six most important event shape variables related to three-particle final states in electron-positron annihilation. The corrections are sizeable for all variables,…
By analyzing 2.93 fb$^{-1}$ of $e^+e^-$ annihilation data taken at the center-of-mass energy $\sqrt s=$ 3.773 GeV with the BESIII detector, we determine the branching fractions of the inclusive decays $D^+\to\phi X$ and $D^0\to\phi X$ to be…
The cross sections for $D^0 {\bar D}^0$ and $D^+D^-$ production at 3.773 GeV have been measured with BES-II detector at BEPC. These measurements are made by analyzing a data sample of about 17.3 $\rm pb^{-1}$ collected at the center-of-mass…
The region of the Galactic center contains several sources which demonstrate their activity at various wavelengths and particularly above several hundred keV. Escape of positrons from such a source or several sources into the interstellar…
The energy interval between the ground and the P-wave excited states of the recently discovered positronium molecule Ps_2 is evaluated, including the relativistic and the leading logarithmic radiative corrections, E_P-E_S = 0.181 586 7(8)…
We measure the cross section of $e^+e^-\rightarrow\eta_c J/\psi$ at the $\Upsilon(nS) (n=1$ -- $5)$ on-resonance and 10.52 GeV off-resonance energy points using the full data sample collected by the Belle detector with an integrated…
We present the third-order QCD prediction for the production of top-anti-top quark pairs in electron-positron collisions close to the threshold in the dominant S-wave state. We observe a significant reduction of the theoretical uncertainty…
A recent report of $e^+ e^- \to D\bar D$ events by the BESIII Collaboration suggests the presence of a structure $R$ at 3900~MeV\@. We argue that this structure, called $G(3900)$ in the past, is not in fact due to a new $c\bar c$ resonance,…
Based on 22.7 fb$^{-1}$ of $e^+e^-$ annihilation data collected at 33 different center-of-mass energies between 3.7730 GeV and 4.7008 GeV with the BESIII detector at the BEPCII collider, Born cross sections of the two processes $e^+e^-\to…
Existing data on the $e^+e^-\to K^+K^-$ cross section at the center-of-mass energy above 2.6 GeV are fitted with a sum of $\psi(3770)$ resonant and continuum contributions. Two solutions for the resonance production cross section are found…
Using a nonrelativistic constituent quark model in which the degrees of freedom are quark-antiquark and meson-meson components, we have recently shown that the $D^{(\ast)}K$ thresholds play an important role in lowering the mass of the…
Topological insulators are attracting considerable interest due to their potential for technological applications and as platforms for exploring wide-ranging fundamental science questions. In order to exploit, fine-tune, control and…
In this work we evaluate the cross section of the process $e^+e^-\to J/\psi \eta_c$ at energy $\sqrt{s}\approx 10.6$ GeV in the Bethe-Salpeter formalism. To simplify our calculation, the heavy quark limit is employed. Without taking the…
The inclusive cross sections for di-hadrons of charged pions and kaons ($e^+e^- \rightarrow hhX$) in electron-positron annihilation are reported. They are obtained as a function of the total fractional energy and invariant mass for any…
Calculations of the relaxation energy, contact pair-correlation function, and annihilating-pair momentum density for a single positron immersed in a homogeneous electron gas are presented. We achieve an accurate description of the…