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QCD Giulia Zanderighi (Max Planck Institute für Physik) 1st Lecture ESHEP School September 2019 Today’s high energy colliders Today’s high energy physics program relies mainly on results from Today’s high energy colliders Collider Process Today’s high statusenergy colliders + T-oday’s high energy colliders Collider LEP/LEP2Process setaetus Today’s high1989-2000energy colliders Today’s chighurrenenergyt and ucpolliderscoming ex- Hera e±p Today’s high1992-2007energy colliders HERCAoll(idAe&r B) Preo±cpess rsutanntuinsg periments collide protons Collider TevatronProcess statupps curre1983-2011nt and upcoming ex- Collider Process status current and upcoming ex- THeERvCaotrlAloidn(eAr(I&&B)II) Proceep±sp¯sp startuunsning cpuerrrimenetntsancdolluidpecopmroitongnsex- HERA (A & B)LHC-e ±Runp I runninppg cpuerrrimenetntsa2010-2012ncadolllluidipnecvopomrolvitonegnQseCDx- Collider Process status THeERvatrALoHn(AC(I&&B)II) ep±p¯p starurtsnn2in0g07 pe⇒riments collide protons THeERvatrAon(A(I&&B)II) ep±p¯p running perimcuernretsnctolalinded puroptoconms ing ex- LHC- Run II pp astartedll inavlloilnv 2015evoQlvCDe QCD THeERvatrALoHn(AC(I&&B)II) ep±p¯p starurtsnn2in0g07 pe⇒riments collide protons TevatrLoHnC(I & II) pp¯ starurtsnn2in0g07 ⇒ all involve QCD LEPHER highA: m precisionainly mea measurementssurements of pa ofrto masses,n denaslilti couplings,iensvaonlvdedQiffr CDEWacti oparametersn ... TevaLtrHLoHCnC(I & II) pppp¯ stasrtstarur2tsn0n02i7n0g07 ⇒ ⇒ Hera: mainly measurements of proton structureal l/ inpartonvolve densitiesQCD HTHEReERLvA:HatrA:Cmonma:inamliynalmyinemlyaesdpuaipsrsecumoreveemnrtseysntaotsffrptsthoafer2top0toan0rp7todaennsddietirene⇒sslaiatitenedds mdainffredaasdcutiiffrroenamcetionnts THTevatron:eLTHERveHERavCtrA:aotrA:dnmoe:nmasm :imainlyngaamlniyinnaelmlyidynemldtoya isdiscoveryesdcuaiosrsevcuemorreveyemnortseyf nthooftsfef pthtoptooaferptopto aaandnnrpdtodaern nemanyslddaietiterenedssla imQCDatiteneeddsasmdauinffr ermeasurementsdeaamsdcuetiiffrronentsamcetionnts LTLHCeHLTveHCERavCtradd odesignedtrA:eidsnsoec:ingmsom:nivgaaemeniidnrnaelthltoyidyn toemldtoyiHsedcaiigossvgcueosrrevyaemnoredyf nthomtsefethtooafespputoaarenrpdtoit’arnsnelddpaerteronedpslaeimtiteretiedseassmaunerdeamsdueiffrrnetsamcetionnts LHLTediscoverHCvdCaiddustreincdssorecaivngsove:nivegrem elnththedrpaeethtooidn sHelHiggstosyigiHbdgiligsesgcap os[donenhvdayesnmridycesoma infsbeuthe arRunyeesouintot’rsde pI]pthit’arosenpdpSMerroetipelaestertidesmeasurements discover the Higgs and measure it’s properties unravelundurinasrvcaeovl vepossiblepelorpsthossiebsleiHb pilgeBSMhgypsshiacy sphysicssnidbcesmyboeenayd s[elusiveouthnrde thSMit’sep SMuprop toer tinow]es LHOuC rdeasbigilintyedtotodiscover new particles and to measure their unravel possible physics beyond th2e SM duinsrcaovveelrpthosesiHbilgegpshaysnidcsmbeeaysounrde thit’sepSMroperties OuOuprrorapbeairlbitityielitystolitomdistedcidosvcbeoyrvthenreewnqeupwaalriptitycaloretifscolaeunsrduantonddemrtosetaasmnuderieansgthuoreefirQCtheDir Ouprorpuenarrbtiaielvitysellitopmoitesdsidsibcbloyevtheprheynqseuiwcasliptybaeorytifocolneudsr uthanneddeSMrtostamndeiansguoref QCtheDir Ouprorpearbtiielitys litomitedidscboyvtherenqeuwaliptyaortifcoleusr uannddertostamndeiansguoref QCtheDir properties limited by the quality of our understanThde oinne-lgoop oamfplitQCude forDsix gluon scattering - April 2006 – p.2/20 Ouprorpearbtiielitys litomitedidscboyvtherenqeuwaliptyaortifcoleusr uaTnhenodndee-loorptosamtaplitumnde dfoer siainx gsgluoun osrcaeftterQCingth- AperDil 2i0r06 – p.2/20 The one-loop amplitude for six gluon scattering - April 2006 – p.2/20 properties limited by the quality of our uTnhe odnee-loorpsamtaplitunde dfor siinx ggluon oscaftterQCing - AprDil 2006 – p.2/20 The one-loop amplitude for six gluon scattering - April 2006 – p.2/20 The one-loop amplitude for six gluon scattering - April 2006 – p.2/20 Today’s status of particle physics • The Higgs boson: the last missing ingredient of the Standard Model of particle physics • The SM is a consistent theory up to very high energy, but it can not be a complete theory because of many theory and experimental puzzles (Dark matter and dark energy, neutrino masses, flavour physics, hierarchy problem, no theory of quantum gravity…) The days of guaranteed discoveries or no-lose theorems are over. Progress will be driven by LHC data. The LHC program in the coming decades will focus on • Direct searches: production of new (heavy status) … • Indirect searches: Higgs couplings and branchings, rare decay modes … • Consistency tests: precision electroweak data 3 Today’s status of particle physics Improving our theoretical description of data crucial to enhance sensitivity when looking for new physics. Example: extraction of Higgs couplings limited by theory uncertainties Sharpen the tools ⇒ get more accurate predictions ⇒ get improved indirect sensitivity to New Physics (which would modify SM couplings) 4 Propose of these lectures In these lectures: perturbative QCD as a tool for precision QCD at colliders • Introduction to QCD (or refresh your knowledge of QCD) • Basic concepts which appear over and over in different contexts • Understand the terminology • Recent developments in the field 5 Some bibliography • A QCD primer G. Altarelli (TASI lectures 2002) hep-ph/0204179 • QCD and Collider Physics (a.k.a. The Pink Book) R.K. Ellis, W. J. Stirling, B. R. Webber, Cambridge University Press (1999) • Foundations of Quantum Chromodynamics T. Muta, World Scientific (1998) • Quantum Chromodynamics: High Energy Experiments and Theory G. Dissertori, I. Knowles, M. Schmelling, International Series of Monograph on Physics (2009) • The theory of quark and gluon interactions F. J. Yndurain, Springer-Verlag (1999) • Gauge Theory and Elementary Particle Physics T. Cheng and L. Li, Oxford Science Publications (1984) • The Black Book of Quantum Chromodynamics: A Primer for the LHC Era J. Campbell, J, Huston, F. Krauss (2018) • many write-ups of QCD lectures given at previous CERN schools ... 6 The beginning: the eightfold way Organise hadron spectrum to manifest some symmetry-pattern One hadron missing, but predicted following the pattern But what is the reason for this pattern? 7 Quarks (1964) Gell-Mann and Zweig propose the existence of elementary spin 1/2 particles (the quarks). Three types of quarks, up, down, strange (plus their antiparticles) can explain the composition of all observed hadrons 8 First experimental evidence for colour I. Existence of Δ++ particle: particle with three up quarks of the same spin and with symmetric spacial wave function. Without an additional quantum number Pauli’s principle would be violated ⇒ color quantum number u1 u2 u3 ++ ∆ = ijkuiujuk New quantum number solves spin-statistics problem (wave function becomes asymmetric) 9 U †U = UU † = 1 det(U) = 1 ψ∗ψ U ∗ ψ U ψ = ψ∗ψ i i → ij j ik k k k !i !ijk !k ψiψjψk U ∗ Ujj Ukk ψi ψj ψk = ψi ψj ψk First→ experimentalii′ ′ ′ ′ evidence′ ′ for′ ′ colour′ !ijk ijk!i′j′k′ i!′j′k′ n n = n 3 with n integer II.R-ratio: ratioq of− (eq¯+e- → ·hadrons)/(e+e- → µ+µ-) e+ p1 + e e− hadrons 2 R + → + Nc Qf ≡ e e− µ µ− ∝ → !f e− p2 Experimental data confirms Nc = 3. (Will come back to R later.) Color becomes the charge of strong interaction. Interaction is so strong, that the only observed hadrons in nature are those where quarks are combined in colour singlet states Colour SU(3) is an exact symmetry of nature 10 1 QCD Model for strong interactions: non-abelian gauge theory SU(3) U †U = UU † = 1 det(U) = 1 ψ∗ψ U ∗ ψ U ψ = ψ∗ψ Hadron spectrum fully classifiedi i → withij thej ik followingk assumptionsk k !i !ijk !k - hadrons (baryons,mesons): made of spin 1/2 quarks ψ ψ ψ U ∗ U U ψ ψ ψ = ψ ψ ψ i j k ii′ jj′ kk′ i′ j′ k′ i′ j′ k′ ijk → ijki j k i j k - each! quark of a given! ′flavour′ ′ comes in Nc=3 colors!′ ′ ′ + e e− hadrons color SU(3) is an exactR symmetry→ Q2 - ≡ e+e µ+mu ∝ − → − - hadrons are colour neutral, i.e. colour singlet under SU(3) - observed hadrons are colour neutral ⇒ hadrons have integer charge 11 1 Color singlet hadrons Quarks can be combined in 2 elementary ways into color singlets of the SUc(3) group Mesons (bosons, e.g. pion ...) ψ∗ψ U ∗ U ψ ψ = ψ∗ψ i i → ij ik j k k k i ijk k Baryons (fermions, e.g. proton, neutrons ...) ⇥ ⇥ ⇥ U U U ⇥ ⇥ ⇥ = det(U)⇥ ⇥ ⇥ ijk i j k → ijk ii jj kk i j k ijk i j k ijk iijjkk ijk 12 Quark mass spectrum 100 up-type quarks t 1 down-type quarks u c t 10− b 2/3 up charm top 2 c + 10− top /m q 3 s 10− d s b m 1/3 electric charge down strange bottom − 4 10− d u 5 1st 2nd 3rd 10− quark generation 6 10− charge 2/3 up charm top mass= few MeV ~1.6 GeV ~172 GeV charge -1/3 down strange bottom mass = few MeV ~100 MeV ~5 GeV 13 The R-ratio: comparison to data Renormalisation group QCD beta function Short-distance observables 2 Comparison of RˆR tochangesexperi mcrossingental d aquarkta flavour thresholds R = Nc eq q 10 2 φ u, d, s ω 3 loop pQCD 10 Naive quark model ρ ρ′ nf =3 R =2 1 Sum of exclusive Inclusive measurements measurements -1 10 0.5 1 1.5 2 2.5 3 7 ψ(2S) J/ψ ψ4160 c 6 Mark-I Mark-I + LGW ψ4415 Mark-II ψ4040 5 PLUTO ψ3770 R DASP 10 4 Crystal Ball BES nf =3 4 R = 3 → 3 2 3 3.5 4 4.5 5 8 Υ(1S) Υ(3S) b 7 Υ(2S) Υ(4S) 6 5 11 4 nf =4 5 R = 3 ARGUS CLEO CUSB DHHM → 3 MD-1 2 Crystal Ball CLEO II DASP LENA 9.5 10 10.5 11 √s [GeV] 14 Andrea Banfi Lecture 2 QCD matter sector e− e− u 2/3 up γ∗ + q d s q 1/3 electric charge down strange − p X 1st 2nd Feynman diagram describing DIS of an quark generation electron on a proton • The light quark's existence was validated by the SLAC's deep
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  • Isospin Symmetry Breaking in Sd Shell Nuclei

    Isospin Symmetry Breaking in Sd Shell Nuclei

    Num´ero d’ordre: 4446 TH ESE` pr´esent´ee `a L’Université Bordeaux I Ecole Doctorale des Sciences Physiques et de l’Ing enieure´ par Yek Wah LAM (Yi Hua LAM 藍藍藍乙乙乙華華華) Pour obtenir le grade de DOCTEUR Sp ecialit´ e´ Astrophysique, Plasmas, Nucl eaire´ Isospin Symmetry Breaking in sd Shell Nuclei Soutenue le 13 decembre 2011 tel-00777498, version 1 - 17 Jan 2013 Apr`es avis de: M. Piet Van ISACKER DR, CEA, GANIL Rapporteur externe M. Frederic NOWACKI DR, CNRS, IHPC, Strasbourg Rapporteur externe Devant la commission d’examen form´ee de: M. Bertram BLANK DR, CNRS, CEN Bordeaux-Gradignan Pr´esident M. Michael BENDER DR, CNRS, CEN Bordeaux-Gradignan Directeur de th`ese M. Van Giai NGUYEN DR, CNRS, IPN, Orsay Examinateurs M. Piet Van ISACKER DR, CEA, GANIL M. Frederic NOWACKI DR, CNRS, IHPC, Strasbourg Mme. Nadezda SMIRNOVA Maˆıtre de Conf´erences, Universit´eBordeaux I 2011 CENBG Dedicated to my beloved wife Mei Chee Chan ഋऍ޲ , and my dear son Yu Xuan Lam ᙔᒕ侍 , without whose consistent encouragement and total sacrifice, this thesis would have never been touched by the light. And dedicated to the late Peik Ching Ho Ֆᅸమ , my grandma who loved me most, tel-00777498, version 1 - 17 Jan 2013 and lost her beloved hubby during WW2, and rebuilt our family determinantly. 2 Acknowledgments As a mechanical engineering graduate, I opted not to follow the ordinary trend of graduates. Most of them have a rather easy life with high income, whereas I have chosen a different path of life – pursuing theoretical physics career – the so-called abnormal path in ordinary Malaysians perspective.
  • Chapter 16 Constituent Quark Model

    Chapter 16 Constituent Quark Model

    Chapter 16 Constituent Quark Model 1 Quarks are fundamental spin- 2 particles from which all hadrons are made up. Baryons consist of three quarks, whereas mesons consist of a quark and an anti-quark. There are six 2 types of quarks called “flavours”. The electric charges of the quarks take the value + 3 or 1 (in units of the magnitude of the electron charge). − 3 2 Symbol Flavour Electric charge (e) Isospin I3 Mass Gev /c 2 1 1 u up + 3 2 + 2 0.33 1 1 1 ≈ d down 3 2 2 0.33 − 2 − ≈ c charm + 3 0 0 1.5 1 ≈ s strange 3 0 0 0.5 − 2 ≈ t top + 3 0 0 172 1 ≈ b bottom 0 0 4.5 − 3 ≈ These quarks all have antiparticles which have the same mass but opposite I3, electric charge and flavour (e.g. anti-strange, anti-charm, etc.) 16.1 Hadrons from u,d quarks and anti-quarks Baryons: 2 Baryon Quark content Spin Isospin I3 Mass Mev /c 1 1 1 p uud 2 2 + 2 938 n udd 1 1 1 940 2 2 − 2 ++ 3 3 3 ∆ uuu 2 2 + 2 1230 + 3 3 1 ∆ uud 2 2 + 2 1230 0 3 3 1 ∆ udd 2 2 2 1230 3 3 − 3 ∆− ddd 1230 2 2 − 2 113 1 1 3 Three spin- 2 quarks can give a total spin of either 2 or 2 and these are the spins of the • baryons (for these ‘low-mass’ particles the orbital angular momentum of the quarks is zero - excited states of quarks with non-zero orbital angular momenta are also possible and in these cases the determination of the spins of the baryons is more complicated).