A search for a massless dark photon $\gamma^{\prime}$ is conducted using 4.5 $\mathrm{fb}^{-1}$ of $e^+e^-$ collision data collected at center-of-mass energies between 4.600 and 4.699 $\mathrm{GeV}$ with the BESIII detector BEPCII. No significant signal observed, upper limit on branching fraction $\mathcal{B}(\Lambda^{+}_{c}\to p \gamma^{\prime})$ determined to be $8.0\times 10^{-5}$ 90% confid...

We calculate the photon pair production rate in a strong magnetic field created in off-central heavy-ion collisions. Photon decay leads to depletion of the photon yield by a few percent at RHIC and by as much as 20% at the LHC. It also generates a substantial azimuthal asymmetry (“elliptic flow”) of the final photon distribution. We estimate v2 ≈ 2% at RHIC and v2 ≈ 14% at LHC. Photon decay mea...

This paper focuses on the optimization of initiating dimensions of groove bearing in association with de- sired design of vehicle’s front structure which is made up of low carbon steels in the case of frontal collision. Axial bearing analysis is done numerically using nonlinear finite element code LS-DYNA. In this analysis, changes of two main parameters including measure of energy absorp...

Abstract The creation of an electron–positron pair in the collision two real photons, namely linear Breit–Wheeler process, has never been detected directly laboratory since its prediction 1934 despite fundamental importance quantum electrodynamics and high energy astrophysics. In last few years, several experimental setup have proposed to observe this process laboratory, relying either on therm...

The forward electroproduction of two light vector mesons is the first example of a collision process between strongly interacting colorless particles for which the amplitude can be written completely within perturbative QCD in the Regge limit with next-to-leading accuracy. This amplitude can be written as a convolution of two impact factors for the virtual photon to light vector meson transitio...

Singlet fission (SF) has the potential to supersede the traditional solar energy conversion scheme by means of boosting the photon-to-current conversion efficiencies beyond the 30% Shockley-Queisser limit. Here, we show unambiguous and compelling evidence for unprecedented intramolecular SF within regioisomeric pentacene dimers in room-temperature solutions, with observed triplet quantum yields...