ﻻ يوجد ملخص باللغة العربية
Using a data set of 2.93 fb$^{-1}$ taken at a center-of-mass energy $sqrt{s}$ = 3.773 GeV with the BESIII detector at the BEPCII collider, we perform a search for an extra U(1) gauge boson, also denoted as a dark photon. We examine the initial state radiation reactions $e^+e^-rightarrow e^+e^-gamma_{rm ISR}$ and $e^+e^-rightarrow mu^+mu^-gamma_{rm ISR}$ for this search, where the dark photon would appear as an enhancement in the invariant mass distribution of the leptonic pairs. We observe no obvious enhancement in the mass range between 1.5 and 3.4 GeV/$c^{2}$ and set a 90% confidence level upper limit on the mixing strength of the dark photon and the Standard Model photon. We obtain a competitive limit in the tested mass range.
The KLOE Experiment at the $phi$ factory DA$Phi$NE, has measured the cross section $sigma(e^+e^-topi^+pi^-gamma)$ using two different selection schemes: requiring the photon emission at small polar angle and detecting the photon at large polar angle
A parameterization of the $bar pp$ differential elastic scattering cross section in the beam momentum range from 2 to 16 GeV/c is proposed. The parameterization well describes the existing data including the observed diffraction pattern at four-momen
A search for hidden photon cold dark matter (HP CDM) using a new technique with a dish antenna is reported. From the result of the measurement, we found no evidence for the existence of HP CDM and set an upper limit on the photon-HP mixing parameter
Identifying the nature and origin of dark matter is one of the major challenges for modern astro and particle physics. Direct dark-matter searches aim at an observation of dark-matter particles interacting within detectors. The focus of several such
We have studied the quasielastic 3He(e,ep)d reaction in perpendicular coplanar kinematics, with the energy and momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The 3He(e,ep)d cross section was measured for missing m