Feebly-interacting particles: FIPs 2020 workshop report

With the establishment and maturation of the experimental programs searching for new physics with sizeable couplings at the LHC, there is an increasing interest in the broader particle and astrophysics community for exploring the physics of light and feebly-interacting particles as a paradigm complementary to a New Physics sector at the TeV scale and beyond. FIPs 2020 has been the first workshop fully dedicated to the physics of feebly-interacting particles and was held virtually from 31 August to 4 September 2020. The workshop has gathered together experts from collider, beam dump, fixed target experiments, as well as from astrophysics, axions/ALPs searches, current/future neutrino experiments, and dark matter direct detection communities to discuss progress in experimental searches and underlying theory models for FIPs physics, and to enhance the cross-fertilisation across different fields. FIPs 2020 has been complemented by the topical workshop Physics Beyond Colliders meets theory, held at CERN from 7 June to 9 June 2020. This document presents the summary of the talks presented at the workshops and the outcome of the subsequent discussions held immediately after. It aims to provide a clear picture of this blooming field and proposes a few recommendations for the next round of experimental results

Nietzsches gelijk: Waarom wijsheid achteraf onbillijk is

A search is performed for a massive new vector-like quark T, with charge 2/3, that is pair produced together with its antiparticle in proton-proton collisions. The data were collected by the CMS experiment at the Large Hadron Collider in 2012 at sqrt(s) = 8 TeV and correspond to an integrated luminosity of 19.5 inverse femtobarns. The T quark is assumed to decay into three different final states, bW, tZ, and tH. The search is carried out using events with at least one isolated lepton. No deviations from standard model expectations are observed, and lower limits are set on the T quark mass at 95% confidence level. The lower limit lies between 687 and 782 GeV for all possible values of the branching fractions into the three different final states assuming strong production. These limits are the most stringent constraints to date on the existence of such a quark

Observation of the diphoton decay of the Higgs boson and measurement of its properties

Peer reviewe

Measurement of the Zγ production cross section in pp collisions at 8 TeV and search for anomalous triple gauge boson couplings

Open Access, Copyright CERN, for the benefit of the CMS Collaboration. Article funded by SCOAP3.Abstract: The cross section for the production of Zγ in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb−1. Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. The differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. The observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. Limits on anomalous triple gauge couplings of ZZγ and Zγγ are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson

Search for lepton-flavour-violating decays of the Higgs boson

Peer reviewe

Search for neutral resonances decaying into a Z boson and a pair of b jets or tau leptons

Peer reviewe

BREMSSTRAHLUNG THERMIQUE COMME SONDE DE LA MULTIFRAGMENTATION NUCLEAIRE DANS LES COLLISIONS NOYAU-NOYAU AUX ENERGIES DE FERMI

CETTE THESE ABORDE L'ETUDE DE LA MATIERE NUCLEAIRE A DES TEMPERATURES ET DES DENSITES MODEREES, TELLE QU'ELLE EST PRODUITE DANS DES COLLISIONS NOYAU-NOYAU A DES ENERGIES INCIDENTES VOISINES DE L'ENERGIE DE FERMI. LA DYNAMIQUE DES REACTIONS ET L'ETAT THERMODYNAMIQUE DES SYSTEMES NUCLEAIRES, CHAUFFES ET COMPRIMES A DES VALEURS OU L'ON S'ATTEND A OBSERVER LA TRANSITION LIQUIDE-GAZ DE LA MATIERE NUCLEAIRE, SONT ETUDIES EN UTILISANT LES PHOTONS DURS (EG>30 MEV) COMME SONDE EXPERIMENTALE. CES PHOTONS DURS SONT EMIS LORS DES COLLISIONS ELEMENTAIRES DE BREMSSTRAHLUNG (RAYONNEMENT DE FREINAGE) ENTRE PROTONS ET NEUTRONS (PN) DANS LA ZONE PARTICIPANTE. POUR LA PREMIERE FOIS, UNE TELLE ETUDE A ETE REALISEE DE FACON SYSTEMATIQUE LORS D'UNE MEME MESURE, EN CONSIDERANT QUATRE SYSTEMES DIFFERENTS (36AR + 197AU, 107AG, 58NI, 12C A 60A MEV), ET EN ANALYSANT DES MODES DE PRODUCTION EXCLUSIFS ET INCLUSIFS. CETTE APPROCHE A ETE RENDUE POSSIBLE EN EXPLOITANT LA COMBINAISON UNIQUE D'UN SPECTROMETRE DE PHOTONS, TAPS, ET DEUX MULTIDETECTORS DE PARTICULES-CHARGES, LE DWARF-BALL ET LE FORWARD-WALL, OFFRANT UNE COUVERTURE DE L'ANGLE SOLIDE VOISINE DE 4PI. NOUS CONFIRMONS L'ORIGINE DOMINANTE DES PHOTONS COMME ETANT DUE AUX COLLISIONS PN DE BREMSSTRAHLUNG DE PREMIER-CHANCE (HORS EQUILIBRE). NOUS ETABLISSONS DE FACON DEFINITIVE L'EXISTENCE D'UNE EMISSION THERMIQUE DE PHOTONS EN REACTIONS SEMI-CENTRALES ET CENTRALES NOYAU-NOYAU IMPLIQUANT DES CIBLES LOURDES ET ATTRIBUONS SON ORIGINE AU BREMSSTRAHLUNG EMIS DANS LES COLLISIONS PN DE DEUXIEME-CHANCE. NOUS EXPLOITONS CETTE OBSERVATION I) POUR DEMONTRER QUE LA MATIERE NUCLEAIRE ATTEINT UN EQUILIBRE THERMIQUE LORS DE LA REACTION, II) POUR VALIDER UN NOUVEAU THERMOMETRE BASE SUR DES PHOTONS DU RAYONNEMENT DE FREINAGE, III) POUR DEDUIRE LES PROPRIETES THERMODYNAMIQUES DE LA MATIERE NUCLEAIRE CHAUDE (EN PARTICULIER, POUR ETABLIR LA COURBE CALORIQUE) ET IV) POUR EVALUER LES ECHELLES DE TEMPS DU PROCESSUS DE FRAGMENTATION. ADDITIONNELLEMENT, DES SIMULATIONS MICROSCOPIQUES DETAILLEES DES QUATRE REACTIONS CONSIDEREES, ONT ETE EFFECTUEES AVEC DEUX MODELES DE TRANSPORT DIFFERENTS BASES SUR L'EQUATION DE TRANSPORT DE BOLTZMANN (BUU) ET SUR LA DYNAMIQUE MOLECULAIRE (QMD), AFIN D'IDENTIFIER DANS L'ESPACE ET LE TEMPS LES SOURCES DES PHOTONS DE BREMSSTRAHLUNG ET DETERMINER LEUR DEGRE DE THERMALIZATION AU MOMENT D'EMISSION DES PHOTONS.CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

Performance studies for the prototype III of CASTOR forward calorimeter at the CMS experiment

We present preliminary results of the performance of prototype III of the CASTOR quartz-tungsten sampling calorimeter, to be installed in the very forward region of the CMS experiment at the LHC. The energy linearity and resolution, as well as the spatial resolution of the prototype to electromagnetic and hadronic showers are studied with E= 10-200 GeV electrons, E= 20-350 GeV pions, and E= 50, 150 GeV muons in beam tests carried out at CERN/SPS in 2007