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NParticlePhysics
ResearchParticlephysics isthestudyofthefundamentalbuildingblocksofmatterandhowthey interactwitheachother.Modernparticlephysicistsbuild largeexperimentswhereparticlesaremade to smash intooneanotherathighenergies.Particledetectorsarebuiltaroundwherethesecollisionsoccur,andwestudytheparticlesresultingfromthecollisioninteractions.
TheLargeHadronCollider(LHC)atCERNiscollidingprotonsathigherenergiesthaneverbefore,andaccumulatingahugedataset, allowing us to probe nature at itsmost fundamental level. The Bristol Particle Physics group is involved in twoexperimentsthatrunattheLHC:CMSandLHCb.Wearealsoinvolvedinavarietyofresearchanddevelopmentprojectsforfutureexperiments.Nowisaveryexcitingtimeinparticlephysics!
TheCMSexperimentatCERN
The Compact Muon Solenoid (CMS) detector is one of two general purposeexperimentsattheLHC.Ithasabroadprogrammeofphysics,includingthediscoveryoftheHiggsbosonandsearchesfornewphysicsbeyondtheStandardModel.
AtBristol,weareleadingthewayindirectsearchesfornewphenomenasuchasdarkmatter, Supersymmetricparticles, andadditional exoticHiggsbosons. Wearealsopreciselymeasuringthepropertiesofthetopquark,toenhanceourunderstandingoftheheaviest knownparticleof theStandardModel. Ourworkon theMasterCodeProject brings together the results of all of these measurements and searches toconstrainmodelsofnewphysics.
Wehavebeenheavily involvedwith thedesignandconstructionof thetracker, theelectromagnetic calorimeter, and the first level trigger for CMS. We continue tocontribute strongly in the day to day running of the CMSdetector, and also in theupgradeofseveralaspectsofthedetector.
ResearchandDevelopmentThe Bristol group is actively researching and developing new solid-state particledetectortechnologies.Thesewillbeusedinfutureparticlephysicsexperiments,suchasupgradestotheLHCexperiments,thesearchforlepton-flavourviolationatMu3e,andtheSiDdetectorattheILCandCLIClinearcolliderexperiments.
We also develop applications of our detector technologies in other fields, such asmedical X-ray therapy and radiation detectors. We are also working on theexploitation of natural cosmic rays to scan shipping containers and nuclear wastecontainersusingResistivePlateChamber(RPC)detectors.
WeareenteringacompletelynewrealmofsensitivitytoNewPhysics.WedonotknowwhichapproachwilldiscoverevidenceofNewPhysicsfirst:thehighlysensitivesearchfordeviationsfromStandardModelpredictionsinprecisionflavourphysicsatLHCbandNA62,ordirectobservationofnewparticlesatCMS.However,itiscertainthattheinputfrombothwillbeneededifwewishnotmerelytobreaktheStandardModel,buttounderstandandexploitthephysicsthatliesbeyondit.
FlavourPhysicsThe detailed study of quark transitions provides insights into the structure of theStandardModel,andallowsthediscoveryandstudyofphysicsbeyondtheStandardModel.Precision flavourphysics is sensitive to loopeffects causedbyparticles thatcanbefarheavierthanthosedirectlyproducedatcolliders—itcanseebeyondtheenergyfrontierbeingprobedbythegeneralpurposedetectorsattheLHC.
Bristol has a comprehensive flavourphysics programme, coveringBphysics (LHCb),charmphysics(CLEO-candLHCb)andkaonphysics(NA62).Theseareascomplementeach other in their sensitivity to New Physics, providing an unprecedentedexperimental precision where a whole host of New Physics models could becomeapparent.Bristolhasoneofthemostfar-reachingprogrammesintheUK.
In addition to our established flavour physics programme, we are expanding ouractivities into the neutrino sector, with a search for sterile neutrinos at the SoLidexperiment,andpreparationsfortheDUNEproject,whichwillstudyhowneutrinososcillate between different flavours over a distance of 1,300km. We are alsocontributingtotheSHiPexperiment,whichaimstohuntfornewweakly interactingparticlesthatwouldbeinaccessibletotheLHCexperiments,aswellasstudyingthetauneutrinoingreatdetail.
