A possible setup for the experimental verification of linear Breit-Wheeler pair creation electrons and positrons in photon-photon collisions is studied theoretically. It combines highly energetic bremsstrahlung photons, which are assumed to be generated by an incident beam GeV penetrating through a high-$Z$ target, with keV photons from x-ray laser field, described as focused Gaussian pulse. We...

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Search for photonic signatures of gauge-mediated supersymmetry in 8 TeV pp collisions with the ATLAS detector G. Aad et al. A search is presented for photonic signatures motivated by generalized models of gauge-mediated supersymmetry breaking. This search makes use of 20.3 fb −...

The Run I results on the searches for new physics in photon final states were intriguing. The rare eeγγ 6ET candidate event and the measured event rate for the signature l + γ + 6ET, which was 2.7 sigma above the Standard Model predictions, sparked signature-based searches in the γγ +X and lγ +X channels. With more data in Run II we should be able to answer a simple question: was it an anomaly ...

A search is presented for photonic signatures motivated by generalized models of gauge-mediated supersymmetry breaking. This search makes use of 20.3 fb−1 of proton-proton collision data at ffiffi s p 1⁄4 8 TeV recorded by the ATLAS detector at the LHC, and explores models dominated by both strong and electroweak production of supersymmetric partner states. Four experimental signatures incorpor...

We have measured the two-photon 2E1 transition from the singlet 1s2s 1S0 to the 1s 1S0 ground state of helium-like tin. The experiment was performed by using initially Li-like tin ions in collision with a nitrogen gas target at the ESR storage ring at the energy of 300 MeV/u. The two-photon emission arises from the decay of the exclusively formed 1s2s states following the ionization of one K-sh...

The emission of hard real photons from thermalized expanding hadronic matter is dominated by the initial high-temperature expansion phase. Therefore, a measurement of photon emission in ultrarelativistic heavy-ion collisions provides valuable insights into the early conditions realized in such a collision. In particular, the initial temperature of the expanding fireball or equivalently the equi...

The grain size effects on the bremsstrahlung emission spectrum due to nonrelativisitc electrondust grain collisions are investigated in dusty plasmas. Using the Born approximation for the initial and final states of the projectile electron, the bremsstranhlung radiation cross section is obtained as a function of the grain size, dust charge, Debye radius, collision energy, and radiation photon e...

We report on a possible application of the HBT phenomenon in testing the existence of two hypothetical phenomena. First, it is argued that the existence of a rapidly developing parton cascade in the earliest stages of a high energy nuclear collision process can be tested by studying two–photon HBT correlations over a wide longitudinal momentum scale – corresponding to the early photon emission ...

This paper provides an updated efficiency analysis of the LightForce space debris collision avoidance scheme. LightForce aims to prevent collisions on warning by utilizing photon pressure from ground based, commercial off the shelf lasers. Past research has shown that a few ground-based systems consisting of 10 kW class lasers directed by 1.5 m telescopes with adaptive optics could lower the ex...

We compute the thermal photon spectrum in the Pb+Pb collisions at the CERN SPS energy using thermal emission rates and a hydrodynamic description for the evolution of produced hot matter and compare our results with the measurements of the excess photons by the WA98 collaboration. Our results show that the measured photon spectrum can be reproduced with realistic initial conditions which take p...