Manfred Jeitler The Physics of LHC Baikal Physics School LHC/LEP SPS CMS ATLAS ALICE LHCb THE PHYSICS OF LHC Manfred Jeitler

Manfred Jeitler The Physics of LHC Baikal Physics School БАК (Большой Адронный Коллайдер)

Manfred Jeitler The Physics of LHC Baikal Physics School THE PHYSICS CASE

Manfred Jeitler The Physics of LHC Baikal Physics School aims of accelerators n energy frontier –find new particles –learn about basics of interactions »“unification” at higher energies: electroweak interactions, grand unification –cosmology: what the universe looked like soon after the Big Bang n intensity frontier –high-precision experiments

Manfred Jeitler The Physics of LHC Baikal Physics School Vom Urknall bis zum...?

Manfred Jeitler The Physics of LHC Baikal Physics School fermions (spin ½) charge 0 +2/3 -1/3 d u u d u d leptonsquarks the Standard Model +1 0 proton neutron baryons interactions strong weak gravitation ? weak W, Z electromagnetic  strong g force carriers = bosons (spin 1) e e     uct dsb

Manfred Jeitler The Physics of LHC Baikal Physics School completing the Standard Model: the W ± and Z 0 bosons (1983) CERN SPS

Manfred Jeitler The Physics of LHC Baikal Physics School completing the Standard Model: the top quark (1995) Tevatron (Fermilab, Chicago)

Manfred Jeitler The Physics of LHC Baikal Physics School fermions (spin ½) charge 0 +2/3 -1/3 leptonsquarks the Standard Model interactions strong weak gravitation ? weak W, Z electromagnetic  strong g e e     uct dsb Astro Accelerator

Manfred Jeitler The Physics of LHC Baikal Physics School The Higgs boson For the Standard Model to be consistent, there has to exist one more particle: the Higgs boson. It has not been found yet. However, many other high- precision measurement have confirmed the Standard Model in an impressive way.

Manfred Jeitler The Physics of LHC Baikal Physics School Peter Higgs in front of LHC-experiment ATLAS

Manfred Jeitler The Physics of LHC Baikal Physics School

Manfred Jeitler The Physics of LHC Baikal Physics School the Standard Model works only with particles which are originally massless! mass is created through interaction with a (hypothetical) Higgs field due to spontaneous symmetry breaking this field is present everywhere in the universe “oscillations” in the Higgs field manifest themselves as Higgs particles, which should be observed at LHC / CERN over the next few years spontaneous symmetry breaking energy Higgs field hot universe (soon after big bang) cold universe (condensates in an asymmetric state with Higgs field) 0 v particles are massless particles acquire mass the Higgs boson

Manfred Jeitler The Physics of LHC Baikal Physics School The Higgs boson n cannot be lighter than GeV/c2 – excluded by direct searches (LEP, “Large Electron-Positron collider, CERN) – some people thought they caught a glimpse of it at LEP (but then LEP was turned off) n should not be too heavy – else problems arise with the physics it’s supposed to explain n maybe “just around the corner” ? – not so good for LHC (“Large Hadron Collider”, CERN): hard to disentangle from background – have to study lots of possible decay channels ! – Fermilab (“Tevatron” collider, Chicago) has been trying hard to find it

Manfred Jeitler The Physics of LHC Baikal Physics School Supersymmetry (“SUSY”) n another 2 open problems in Standard Model: n “running coupling constants” of electromagnetic, weak and strong interactions meet almost but not completely at the same point n to avoid quadratic divergences in Higgs mass, “fine-tuning” is needed n both problems can be solved by introducing a symmetry between bosons and fermions

Manfred Jeitler The Physics of LHC Baikal Physics School bosons SUSY SUSY particles. green: known particles of the Standard Model red: hypothetical new particles for each known elementary particle there should exist a supersymmetric partner fermions Supersymmetry

Manfred Jeitler The Physics of LHC Baikal Physics School massive astrophysical cosmic halo objects? weakly interacting massive particles? questions of cosmology to particle physics: Why is there more matter than anti-matter in the universe? What is the universe made of? What is dark matter? What is dark energy?  answers to these questions concerning the largest scales might come from the physics of the smallest scales - elementary particle physics dark matter: MACHOS vs WIMPS

Manfred Jeitler The Physics of LHC Baikal Physics School experimental observation of SUSY particles ? Looking for these new supersymmetric particles was/is one of the most important tasks of the major experiments at the Tevatron in Chicago, USA, at the LHC at CERN (Geneva, Switzerland) and at the planned e + e - linear collider. SUSY particles may show very clear signatures due to cascade decays

Manfred Jeitler The Physics of LHC Baikal Physics School important questions of today’s particle physics (ongoing experiments) Where do particles get their mass from? (by interaction with the Higgs particle?) Why are these masses so different? Is there an overall (hidden) symmetry such as supersymmetry (SUSY)  “mirror world” of all known particles?. What is the nature of “dark matter” and “dark energy” in the universe? Why is there more matter than anti-matter? Why have neutrinos such small mass? Is there a Grand Unification which combines all interactions, including gravitation? Are there extra dimensions, D > 4 ? (  string theory, …)

Manfred Jeitler The Physics of LHC Baikal Physics School ACCELERATORS

Manfred Jeitler The Physics of LHC Baikal Physics School Cockroft-Walton accelerator at CERN

Manfred Jeitler The Physics of LHC Baikal Physics School inside of an Alvarez-type accelerating structure

Manfred Jeitler The Physics of LHC Baikal Physics School Synchrotron elements of a synchrotron quadrupole magnet: focussing dipole magnet: to keep particles on track high-frequency accelerating cavity

Manfred Jeitler The Physics of LHC Baikal Physics School SPS Tunnel Super-Proton-Synchrotron (Geneva)

Manfred Jeitler The Physics of LHC Baikal Physics School

Manfred Jeitler The Physics of LHC Baikal Physics School Professor BaikalixProfessor Cernix Astroparticles with eV !! Collisions at 7 TeV !! Summer student in Bolshie Koty

Manfred Jeitler The Physics of LHC Baikal Physics School quadrupole dipole resonator reaction products interaction zone layout of a circular collider

Manfred Jeitler The Physics of LHC Baikal Physics School first electron-electron collider: Novosibirsk / Russia VEP MeV

Manfred Jeitler The Physics of LHC Baikal Physics School superconducting RF cavity from LEP

Manfred Jeitler The Physics of LHC Baikal Physics School electrons vs. protons +30 MinBias

Manfred Jeitler The Physics of LHC Baikal Physics School n electrons (or other leptons): elementary –no substructure –few tracks –sharp energy n protons (hadrons): compounds made up of quarks –what collides is one quark or gluon with another quark or gluon –lots of other “spectators” »mess up the picture –never know collision energy of interacting constituents »only maximum elementary particle or not?

Manfred Jeitler The Physics of LHC Baikal Physics School n scales with 4 th power of Lorentz factor n energy loss per turn: n or synchrotron radiation

Manfred Jeitler The Physics of LHC Baikal Physics School velocity

Manfred Jeitler The Physics of LHC Baikal Physics School n to lose less energy you may –make particles heavier (4 th power!) –make accelerator bigger (only linear) n electron synchrotron with same losses as LHC : –LHC circumference: 27 km n 27 * ~ 4 * km ~ 40 lightyears synchrotron radiation

Manfred Jeitler The Physics of LHC Baikal Physics School

Manfred Jeitler The Physics of LHC Baikal Physics School Collisions at the TeV scale

Manfred Jeitler The Physics of LHC Baikal Physics School LHCILC e – e +  Z H Z  e – e +, H  b b … Example: simulated Higgs event –

Manfred Jeitler The Physics of LHC Baikal Physics School n electron colliders: accelerating RF-cavities to make up for synchrotron losses n proton colliders: dipole magnets to keep protons on a circular track –conventional (“warm”) magnets: ohmic losses –superconducting magnets: cryogenics »LHC cryogenics: ~30 MW out of total of 180 MW for all of CERN –“there is no such thing as a free lunch” what do you spend your money on (electricity bill)?

Manfred Jeitler The Physics of LHC Baikal Physics School n proton colliders are “discovery” machines –proton-antiproton or proton-proton –SPS: W, Z bosons »Super Proton Synchrotron, CERN –Tevatron: top quark »Fermilab, Chicago –LHC, CERN: ??? »Large Hadron Collider n electron-positron colliders allow for precision measurements –LEP: precision measurments of Z mass »Large Electron-Positron Collider, CERN “discovery” vs. “precision” machine

Manfred Jeitler The Physics of LHC Baikal Physics School question (homework) n a text in a Cern exhibition states: “the force of the LHC beam is comparable to that of a herd of running elephants” n is this correct? help: n what could be meant by “force”? –momentum? –kinetic energy? n remember the energy and number of particles in LHC –3.5 TeV, protons per bunch, ~3000 bunches n how heavy and fast is an elephant? –which kind? Indian / African / Siberian?

Manfred Jeitler The Physics of LHC Baikal Physics School another question (more homework) n another text says: “the energy of a particle in LHC is the same as that of a flying mosquito” n is this correct? n is there a contradiction to the statement about elephants? help: n how heavy and fast is a mosquito? –Siberian mosquito compared to Indian elephant

Manfred Jeitler The Physics of LHC Baikal Physics School yet another question (still more homework) n the frequency of the LHC clock at “flat top” (3.5 TeV) is roughly 40 MHz n does the clock frequency at injection (450 GeV) have to be different? –why? n if yes, what is the change of clock frequency during the “ramp” ? –acceleration period, when particle energy and magnetic field rise n could this be a problem?