Conveners
Gamma-Gamma Collisions
- Lucian Harland-Lang (IPPP Durham)
Gamma-Gamma Collisions
- Lucian Harland-Lang (IPPP Durham)
Gamma-Gamma Collisions
- Lucian Harland-Lang (IPPP Durham)
In this talk, I will talk about recent progresses by two-photon processes at Belle. (a) meson transition form factor (TFF), a important input for calculation of hadronic light-by-light scattering contribution, which is one of dominant theory uncertainty source to muon g-2. With single tag method, the pi0/f0(980)/f2(1270) TFF is presented in this talk. (b) The cross section of hadron pair...
We study process e+e- -> e+e-eta' in the double-tag mode and measure for the first time the gamma gamma -> eta' formfactor
F(Q^2_1,Q^2_2) in the momentum-range 2 < Q^2_1,Q^2_2 < 60 GeV^2. The analysis is based on data with an integrated luminosity
469 fb^-1 collected at the PEP-II e+e- collider with the BABAR detector at center-of-mass energies near 10.6 GeV. The results for the formfactor...
The KLOE-2 experiment completed its data-taking at the e+e- DAPHNE collider in Frascati, achieving the integrated luminosity goal of more than 5 fb-1 at the phi peak. KLOE-2 represents the continuation of KLOE with an upgraded detector and an extended physics program. The new four stations installed to tag electrons and positrons from the reaction e+e- -> e+e-gammagamma -> e+e-X, give the...
Motivated by the recent developments in data-driven approaches to improve the hadronic light-by-light scattering calculations of the Standard Model prediction of the anomalous magnetic moment of the muon $a_\mu$, the BESIII collaboration has embarked on a dedicated two-photon physics program. The momentum dependence of transition form factors of single pseudoscalar mesons, as well as of...
We present the observation of the light-by-light scattering process, γγ → γγ, in lead-lead collisions at √sNN = 5.02 TeV. The analysis is conducted using 1.73nb-1 of data collected in November 2018 by the ATLAS experiment at the LHC. Light-by-light scattering event candidates are selected in events with two photons produced exclusively, with small diphoton transverse momentum and small...
Measurements with photon-photon collisions in CMS are reviewed.
Magnetic monopoles are present in generic classes of models beyond the Standard Model and there are currently searches underway for them at the LHC. The strong magnetic fields present in peripheral heavy ion collisions can produce monopoles by the (dual) Schwinger effect. I will outline recent progress in understanding this process and argue that heavy ion collisions may be the most...
So far light-by-light scattering ($\gamma\gamma\to\gamma\gamma$) was not accessible for experiments because the corresponding cross section is rather low. Measurements of diphotons in ultra-peripheral collisions (UPCs) of lead-lead have been reported recently by the ATLAS [1] and CMS Collaborations [2]. Our theoretical results based on equivalent photon approximation in the impact parameter...
In this talk we will present a brief review of the recent results for the particle production by $\gamma \gamma$ interactions at $pp/pA/AA$ collisions. In particular, the dilepton production will be discussed, as well the background associated to pomeron induced interactions. Finally, the probe of the X(4350) in $\gamma \gamma$ interactions at the LHC will be discussed.
The talk presents the LUXE experiment which plans on using the European XFEL electron beam at DESY with an energy of 17.5 GeV and a high intensity optical laser to study non-perturbative QED phenomena. The main focus of the experiment will be the measurement of the rate of laser assisted electron-positron pair production in collisions of high energy photons with an intensive laser beam and...
Photon-induced processes in proton-proton interactions have become recently very topical. The large energy at the LHC, when combined with relatively large luminosity at run II, allows to start the exploration of such processes.
We discuss production of $W^+ W^-$ pairs and $t \bar t$ quark-antiquark pairs in proton-proton collisions induced by two-photon fusion including, for a first time,...
We analyze in detail the LHC prospects for charged electroweakino searches, decaying to leptons, in compressed supersymmetry scenarios, via exclusive photon-initiated pair production. This provides a potentially increased sensitivity in comparison to inclusive channels, where the background is often overwhelming. We pay particular attention to the challenges that such searches would face in...
The analytical asymptotic cross section for arbitrary masses was given a few years ago.
Obtaining an analytical approach of the onset of the asymptotic regime is an interesting challenge.
The current status will be reviewed.
We discuss $\gamma^* \gamma^* \to \eta_c(1S)\, , \,\eta_c(2S)$ transition form factor for both virtual photons. The general formula is given. We use different models for the $c \bar c$ wave function (LFQM or the ones obtained from the solution of the Schr\"odinger equation for different $c \bar c$ potentials: harmonic oscillator, Cornell, logarithmic, power-law and Buchm\"uller-Tye).
We...
