Related papers: Anomalous gamma gamma interaction
We present the measurements of strange and multi-strange hadrons in high energy pp and Pb-Pb collisions at the Large Hadron Collider (LHC) at CERN. The data for these measurements were collected by the ALICE detector in 2010 and 2011. By…
The possible form of New Physics (NP) interactions affecting the ZZZ, $ZZ \gamma$ and $Z\gamma \gamma$ vertices, is critically examined. Their signatures and the possibilities to study them, through ZZ and $Z\gamma$ production, at the…
In this work we analyse the possibility of constraining the QCD dynamics at high energies studying the heavy quark photoproduction at LHC in coherent interactions. The rapidity distribution and total cross section for charm and bottom…
We present the results from the heavy quarks and quarkonia working group. This report gives benchmark heavy quark and quarkonium cross sections for $pp$ and $pA$ collisions at the LHC against which the $AA$ rates can be compared in the…
Current theoretical framework for the calculation of heavy quark production in $\gamma\gamma$ collisions is reviewed. The importance of including direct photon contributions up to the order $\alpha^2\alpha_s^2$ and of the proper choice of…
A first measurement of the cross section of the process e+e- -> Z gamma gamma is reported using a total integrated luminosity of 231 pb^-1 collected with the L3 detector at centre-of-mass energies of 182.7 GeV and 188.7 GeV. By selecting…
We calculate the cross section for inclusive prompt photon production in $\gamma\gamma$ collisions, i.e. the reaction $e^+e^-\to \gamma \gamma \to \gamma X$, in next-to-leading order QCD. We show that at LEP2 energies this cross section is…
Hard pQCD processes taking place in ultrarelativistic heavy-ion collisions are a well-calibrated probe. It is believed that the interaction with the surrounding medium of outgoing partons from a hard vertex is capable of revealing details…
Drees and Godbole have proposed that, at the interaction point of an e+e- linear collider, one expects a high rate of hadron production by gamma-gamma collisions, providing an additional background to studies in e+e- annihilation. Using a…
In high-energy nuclear collisions, the new phase of the quark-gluon plasma is indicated by an anomalous increase in pressure, an excess of direct photon production, an excess of strangeness production, and an anomalous J/psi suppression. We…
The current status of tests of the theory of strong interactions, Quantum Chromo Dynamics (QCD), with data from hadron production in e^+e^- annihilation experiments is reviewed. The LEP experiments ALEPH, DELPHI, L3 and OPAL have published…
We consider $e e q q$ contact interactions as a possible origin of an excess of events above Standard Model predictions in $e^+ p \to e^+ jet$ at high $Q^2$ observed by the H1 and ZEUS collaborations at HERA. The HERA data prefer chirality…
We report on a search for compositeness in ee+gamma events and a search for gauge-mediated supersymmetry in gamma+gamma+met events. We also report on two signature-based searches for anomalous production of gamma + gamma + X (where X=e, mu,…
In this letter we report on a calculation of W gamma gamma + jet production at next-to-leading order QCD. We include the leptonic decays of the W and take into account all off-shell and finite width effects. This is the first computation…
The $e^{+}\,e^{-}\,\rightarrow\,l^{+}\, \l^{-}\,\gamma\,\gamma$ anomalous events, detected by $L3$ de\-tec\-tor at $e^+ e^-$ $CERN-LEP$ collider have been analysed. It has been shown that the interpretation of such events as a manifestation…
The spectra of strange hadrons are measured in proton-proton collisions, recorded by the CMS experiment at the CERN LHC, at centre-of-mass energies of 0.9 and 7 TeV. The K^0_s, Lambda, and Xi^- particles and their antiparticles are…
We explore the influence of an anomalous chromomagnetic moment, $\kappa$, onthe production characteristics of top quark pairs at the Tevatron. We find that for top quarks in the 170 GeV mass range, present searches are probing values of…
Anomalous chromomagnetic and chromoelectric dipole moments of the top quark may arise from various high scale theories. We carry out a model independent study of such interactions focusing on the limits that can be obtained from current…
We estimate the high-energy behavior of the $\Theta^+$ and $\Lambda(1520)$ production cross sections in inclusive $pp$ collisions using the $K$ exchange diagram. We show that the cross section of the $\Theta^+$-production is suppressed…
Prompt photon production in ultra-relativistic heavy-ion collisions provides a calibrated probe for the study of the properties of high energy density QCD matter. Especially interesting are the measurements of $\gamma$-tagged jets where the…