Understanding the Matter-Antimatter Asymmetry of the Universe. Romulus Godang

Transcription

1 Understanding the Matter-Antimatter Asymmetry of the Universe Understanding the Matter-Antimatter Asymmetry of the Universe (page 1)

2 Fundamental Particle What is the world made of? In ancient times, people sought to organize the world into fundamental elements: earth, air, fire, and water. Who first classified these fundamental elements? Greek thinker Empedocles (500 BC) Are they really the fundamental elements? Understanding the Matter-Antimatter Asymmetry of the Universe (page 2)

3 Fundamental Particle... The ancient Chinese believed 5 basic elements: Wood Metal Earth Fire Water The ancient India proclaimed 5 basic elements: Space Air Fire Water Earth Understanding the Matter-Antimatter Asymmetry of the Universe (page 3)

4 Is the Atom or Nucleus Fundamental? Fundamental building blocks mean objects that are simple and structureless Scientists originally thought the nucleus was fundamental BUT later they discovered that nucleus was made of protons and neutrons Understanding the Matter-Antimatter Asymmetry of the Universe (page 4)

5 The Birth of the Universe After the Big bang exploded with enormous energy, the universe began to cool-down that has lasted until our own time BUT we don t know what made the Big Bang happen in the first place Understanding the Matter-Antimatter Asymmetry of the Universe (page 5)

6 The Standard Model Theory All the known matter particles are composites of 6 quarks and 6 leptons and they interact by exchanging force carrier particles: Electromagnetic (γ), Weak (Z 0, W ± ), and Strong (gluons) Gravity (not yet in the model...) Understanding the Matter-Antimatter Asymmetry of the Universe (page 6)

7 The Standard Model Theory... Hadrons are composite particles made of quarks: Baryons are any hadron which is made of three quarks (qqq) proton (uud) and antiproton (ūū d) Mesons contain one quark (q) and one antiquark ( q) B 0 (d b) and B 0 ( db) Understanding the Matter-Antimatter Asymmetry of the Universe (page 7)

8 Looking for New Particles All new particles are named with Greek letters We have discovered about 200 particles Enrico Fermi (Nobel 1938) said to his student Leon Lederman (Nobel 1988): Young man, if I could remember the names of these particles, I would have been a botanist! All measurements are combined and listed in one book by Particle Data Group (PDG) at Berkeley University. PDG is an international collaboration charged with summarizing Particle Physics and related areas of Cosmology and Astrophysics since PDG published 1200-page book, all years it has been cited in 24,000 times U. Miss has significantly contributed to and member of PDG (R. Godang) Understanding the Matter-Antimatter Asymmetry of the Universe (page 8)

9 What Do We Know about Matter and Antimatter? Antimatter is a mirror image of matter Particle and antiparticle have identical mass and spin BUT opposite charges Neutral bosons (e.g. Z 0, γ) have their own antiparticles The antimatter introduced by Paul Dirac (Nobel Prize 1933) in 1928 Dirac s equation electron with ± energy 1932 Carl Anderson discovered the positron in a cloud chamber Frederic and Irene Curie found positrons emission The Big Bang produced matter and antimatter in equal numbers Our universe is the absence of antimatter (we live in a universe of matter) What happened to the antimatter...? Understanding the Matter-Antimatter Asymmetry of the Universe (page 9)

10 What Happened to the Antimatter? How do we know there is no antimatter around? When a matter and antimatter meet, they annihilate into pure energy, leaving only photons and neutrinos The fact: we don t see this kind of energy in our daily life Can we see the evidence of antimatter? The magnetic field makes negative particles curl left, positive particles curl right Understanding the Matter-Antimatter Asymmetry of the Universe (page 10)

11 Why the Universe is Made Exclusively of Matter? Andrei Sakharov (1967): Baryon violating interactions Thermal non-equilibrium situation CP violation Testing the Sakharov s criteria: There is no direct evidence that baryon number is violated There is a prediction of proton decay: p e + + π 0 but the predicted proton lifetime is year (not observed) In thermal equilibrium the particle density depends only on the particle mass and temperature. They are identical in CPT theorem NO asymmetry Understanding the Matter-Antimatter Asymmetry of the Universe (page 11)

12 CP Violation in Weak Interaction C (Charge Conjugation Invariance) Charge conjugation invariance is broken in weak interaction Right-handed neutrinos (left-handed antineutrinos) are not seen P (Parity) = the flip in the sign of all spatial coordinates Parity is broken in weak interaction There is no left-handed antiparticles CP: Charge Conjugation with Parity Invariance CP is conserved in weak interaction (left-handed neutrino) but... Christension, Cronin, Fitch and Turlay have discovered CP violation in Kaon system (1964) confirmed by KTEV (Fermilab) and NA48 (CERN) Understanding the Matter-Antimatter Asymmetry of the Universe (page 12)

13 The B Meson Factories BABAR at Stanford Linear Accelerator Center Another B-factory machine is at KEKB (Tsukuba) in Japan Understanding the Matter-Antimatter Asymmetry of the Universe (page 13)

14 CP Violation in B Meson BABAR and Belle directly measured CP violation in B system BABAR : e + (3.1 GeV) - e (9 GeV) Belle : e + (3.5 GeV) - e (8 GeV) In 1999 BABAR and Belle had first colliding beam In 2001 BABAR and Belle reported the first measurement of direct CP violation in B meson fundamental matter-antimatter asymmetry Understanding the Matter-Antimatter Asymmetry of the Universe (page 14)

15 The BABAR Collaboration U. Mississippi group: L. Cremaldi, V. Eschenburg, R. Godang, R. Kroeger J. Reidy, D. Sanders, D. Summers, and H. Zhao Understanding the Matter-Antimatter Asymmetry of the Universe (page 15)

16 Physics at B Factories 25 e + e γ ϒ(4S) b d d b B 0 B 0 σ (e + e - Hadrons)(nb) ϒ(1S) ϒ(2S) ϒ(3S) ϒ(4S) Mass (GeV/c 2 ) All B physics based on Υ (4S) decays including CP violation measurement U. Miss published B(Υ (4S) B 0 B 0 ) in PRL 95, , 2005 (R. Godang) B(Υ (4S) B 0 B 0 ) f 00 = ± stat ± syst data, single tags B - 0 signal data, double tags B - 0 signal Candidates/(0.17 GeV 2 /c 4 ) BB - peaking BB - combinatoric Candidates/(0.17 GeV 2 /c 4 ) BB - peaking BB - combinatoric M 2 ν (GeV 2 /c 4 ) M2 2 ν (GeV 2 /c 4 ) Understanding the Matter-Antimatter Asymmetry of the Universe (page 16)

17 The CKM Matrix In SM, quark can change flavor by weak interactions: d s = b V ud V us V ub V cd V cs V cb V td V ts V tb d s b Cabibbo-Kobayashi-Maskawa (CKM) matrix [Weak eigenstates] = [V CKM ] [quark mass eigenstates] The CKM matrix contains real and imaginary numbers (complex numbers) Wolfenstein s CKM matrix form: V CKM = λ2 λ Aλ 3 (ρ iη) λ λ2 Aλ 2 Aλ 3 (1 ρ iη) Aλ 2 1 Four independent parameters: A, ρ, η, and λ 0.22 (expansion parameter) A, ρ, η are real numbers and can be measured in B decays Understanding the Matter-Antimatter Asymmetry of the Universe (page 17)

18 The CKM Matrix... By applying the unitarity condition (scalar product of any two rows or columns): V ub V ud + V cb V cd + V tb V td = 0 CKM matrix can be presented by a triangle in the complex plane b ul ν B + - π π B 0 B 0 mixing B ργ * ud ub V V γ α V cd Vcb * V V * td tb β B S ρk S B + D 0 cp K + B ππ, Κπ b cl ν B ψk S It is very important to measure the CKM angles and its sides! We need to measure them precisely in order to search for New Physics Understanding the Matter-Antimatter Asymmetry of the Universe (page 18)

19 The Unitarity Triangle (UT) The UT sides R u and R t can be expressed: η (ρ,η) α R u R t R u = V ud V ub V cd V cb γ (0,0) (1,0) ρ = 2 + η 2 R t = β V td V tb V cd V cb ρ = (1 ρ) 2 + η 2 The angles α, β, and γ are defined by α = arg [ V tdvtb ] V ud Vub, β = arg [ V cdvcb ] V td Vtb, γ = arg [ V udvub ] V cd Vcb B factories and other experiments measure (α = π β γ) cosγ = ρ/r u, sinγ = η/r u cosβ = (1 ρ)/r t, sinβ = η/r t Understanding the Matter-Antimatter Asymmetry of the Universe (page 19)

20 How to Measure the UT The Unitarity Triangle plane for the relevant observables: 2 sin γ sin 2β sin γ sin 2β K + π + νν m d 0.5 ε, /ε K, K 0 L π 0 νν α η 0 ε K γ β K 0 π 0 νν -0.5 V ub /V cb sin 2α -1 sin 2α -1.5 K + π + νν ε K ρ Sin 2β (CP violation) measurement is the main goal of BABAR and Belle Surprisingly BABAR and Belle discovered several other new particles: massive particle Y(4260) (2005) and Ds (2317) (2003) Understanding the Matter-Antimatter Asymmetry of the Universe (page 20)

21 CP Violation in B System The time evolving B 0 or B 0 to its final CP eigenstates: a fcp = Γ(B0 phys (t) f CP ) Γ(B 0 phys (t) f CP ) Γ(B 0 phys (t) f CP )+Γ(B 0 phys (t) f CP ) a fcp = 1 λ f CP 2 cos( mb t) 2Imλ fcp sin( mb t) 1+ λ fcp 2 where: λ fcp = q p Ā fcp A fcp, A fcp = amplitude of final CP eigenstates q p = m B i 2 Γ B, where p and q are the complex coefficients 2(M 12 i 2 Γ 12) There are 3 ways to measure CP Violation in B decays: Direct CP violation in B decays (B 0 and B ± decays) Āf CP A fcp 1 CP violation in pure mixing (only B 0 decays) q p 1 CP violation in the interference between decays with or without mixing λ fcp = 1, Im(λ fcp ) 1 Understanding the Matter-Antimatter Asymmetry of the Universe (page 21)

22 CP Violation in B System... Understanding the Matter-Antimatter Asymmetry of the Universe (page 22)

23 How to measure CP Violation in B System The time-dependent CP violation asymmetry: A CP ( t) f +( t) f ( t) f + ( t) + f ( t) = η f sin2β sin ( m d t), where η f = ±1, CP eigenvalue of the final state f m d = the B 0 B 0 oscillation frequency t = t rec t tag, βγ = 0.56, z βγc t z = βγcτ B µm β = arg ] [ V cdv cb V td Vtb β is the angle of the UT of the CKM matrix The direct measurement of sin2β is the CP asymmetry Understanding the Matter-Antimatter Asymmetry of the Universe (page 23)

24 CP Violation Result The number of B 0 (N B 0) and B 0 (N B 0) tags The asymmetry (N B 0 N B 0)/(N B 0 + N B 0) as a function of t Understanding the Matter-Antimatter Asymmetry of the Universe (page 24)

25 The Current CP Violation Status D CP K A CP+ D CP K A CP- D CP K* A CP+ D* CP K A CP+ D* CP K A CP- D CP K* A CP- A CP Averages BaBar 0.35 ± 0.13 ± 0.04 HFAG HFAG HFAG Jan 2006 Jan 2006 HFAG Jan 2006 HFAG Jan 2006 Belle 0.07 ± 0.14 ± 0.06 Average 0.23 ± 0.10 BaBar ± 0.13 ± 0.04 Belle ± 0.14 ± 0.05 Average ± 0.10 BaBar ± HFAG Jan 2006 Jan 2006 H F A G H F A G Jan 2006 PRELIMINARY Belle ± 0.25 ± 0.04 Average ± 0.17 Belle 0.26 ± 0.26 ± 0.03 Average 0.26 ± 0.26 BaBar ± 0.19 ± 0.08 Belle ± 0.33 ± 0.07 Average ± 0.18 BaBar ± 0.40 ± 0.12 Belle 0.19 ± 0.50 ± 0.04 Average ± Understanding the Matter-Antimatter Asymmetry of the Universe (page 25)

26 The Current CP Violation Status... b ccs η K 0 π 0 K S ω K S φ K 0 f 0 K S π 0 π 0 K S K + K - K 0 K S K S K S sin(2β eff )/sin(2φ e 1ff ) H F A G HEP 2005 PRELIMINARY World Average 0.69 ± 0.03 BaBar 0.50 ± HFAG HEP 2005 HFAG HEP 2005 HEP HFAG 2005 Belle 0.44 ± 0.27 ± 0.05 Average 0.47 ± 0.19 BaBar 0.36 ± 0.13 ± 0.03 Belle 0.62 ± 0.12 ± 0.04 Average 0.50 ± 0.09 HEP HFAG 2005 BaBar ± 0.10 HFAG HEP 2005 HFAG HEP 2005 Belle 0.47 ± 0.36 ± 0.08 Average 0.75 ± 0.24 BaBar ± 0.04 Belle 0.22 ± 0.47 ± 0.08 Average 0.31 ± 0.26 BaBar ± 0.71 ± 0.08 Average ± 0.71 BaBar ± 0.02 Belle 0.95 ± HFAG Average 0.63 ± 0.30 BaBar 0.41 ± 0.18 ± 0.07 ± 0.11 HFAG HEP 2005 HFAG HEP 2005 HEP 2005 Belle 0.60 ± 0.18 ± Average 0.51 ± BaBar ± 0.04 Belle 0.58 ± 0.36 ± 0.08 Average 0.61 ± Understanding the Matter-Antimatter Asymmetry of the Universe (page 26)

27 The Unitarity Triangle Sides B factories has improved our understanding of CP violation : excluded at CL > 0.95 sin 2β = ± (a precision measurement of 4.7%) This precision outstripped the other measurements As for today measurements V ub and V cb are complementary to sin 2β excluded at CL > 0.95 η excluded area has CL > 0.95 sin 2β γ α sol. w/ cos 2β < 0 (excl. at CL > 0.95) 0.1 γ β Using only angle measurements ρ α C K M f i t t e r EPS 2005 η excluded area has CL > 0.95 sin 2β ε K m d γ α m s & m d sol. w/ cos 2β < 0 (excl. at CL > 0.95) 0.1 V ub /V cb γ β Without angle measurements ρ α C K M f i t t e r EPS 2005 It is clear that we have to make the green ring ( V ub V cb ) thinner in order to make a stringent test on the Standard Model We need to improve a precision of V ub (especially) and V cb Understanding the Matter-Antimatter Asymmetry of the Universe (page 27)

28 Semileptonic B Decays Why do we use semileptonic B Decays? Simple theoretical description at parton level B flavor can be identified from charge of lepton Coupling at W is proportional to V ub and V cb which is directly related in its decay rate : Γ(b ulν) = Γ(b clν) = G2 F 192π 2 V ub 2 m 5 b G2 F V 192π 2 cb 2 m 2 b (m b m c ) 3 Experimental Approaches : Sensitive to strong interactions in B decays Exclusive measurements need form factors to describe the B transition Inclusive measurements need Operator Product Expansion (OPE) and b mass to extract V xb Understanding the Matter-Antimatter Asymmetry of the Universe (page 28)

29 The Unitarity Triangle Status The current average angle results: α = (92.1 ± 5.1) ; β = (24.6 ± 1.7) ; γ = (63.1 ± 5.0) A precision measurement of V ub V cb would significantly improve the constraints on the Unitary Triangle in SM = It could benchmark for New Physics Current precision of V ub and V cb measurements : ( V ub V ub ) = (3.3 exp ± 2.9 model ± 4.7 SF ± 4.0 th )% = 7.6% ( V cb V cb ) = 2%. (OPE fit of E l and M X moments by BABAR ) = It contributes directly to a precision of ( V td V td ) BABAR has double the data in 2006 (0.5 ab 1 ) We hope to quadruple the data by 2008 (1 ab 1 ) Understanding the Matter-Antimatter Asymmetry of the Universe (page 29)

30 Search for Higgs Particle How the elementary particles get their mass? Higgs mechanism (Peter Higgs, 1964) play a central role in the unification of electromagnetic and weak interaction by providing W ± and Z 0 bosons It implies the existence of a single neutral scalar particle so called Higgs particle yet Leon Lederman called it God particle The challenge: Higgs mass is a free parameter in the SM what is the Higgs mass range? The first search of Higgs was done by LEP, CERN (2003) yield a lower limit: M H > GeV (C.L. only) Can Fermilab (D0 and/or CDF) discover the Higgs particle before the more powerful collider, LHC turn on (2007)? (U. Miss at D0: B. Quinn and A. Melnitchouk) Understanding the Matter-Antimatter Asymmetry of the Universe (page 30)

31 Search for Higgs Boson Status January 8, 2007: CDF measured the mass of W : M W = 80, 413 ± 48 MeV the new average M W = 80, 398 ± 25 MeV upper limit of M H down from 166 GeV to 153 GeV Tevatron is only capable of finding Higgs if M H 170 GeV Fermilab has a good change to find Higgs! ) (pb) (*) σ BR(H WW Excluded at LEP (*) H WW lνl ν 95% CL Limit Expected Observed 4th Generation Model Standard Model -1 DØ, 320 pb ) (pb) * x BR(H WW 95% C.L. σ H Excluded LEP 4th Generation Model Standard Model Expected Limit 95% C.L. Limit Higgs mass (GeV) Higgs Mass (GeV/c ) Understanding the Matter-Antimatter Asymmetry of the Universe (page 31)

32 Search Higgs at Muon Collider Unique features of a Muon Collider (µ + µ ): Bremsstrahlung radiation effect is negligible (scales by m 4 µ ) so it does not limit their circular acceleration to reach multi-tev energies Direct s-channel coupling (Mandelstam) to Higgs boson resonances is 40,000 (m µ /m e ) 2 > in (µ + µ h) than in (e + e h) = R (µ+ µ ) higgs R (e+ e ) higgs µ + b (t ) h µ ~m µ ~m b (m t ) b (t ) U. Miss at Muon Collider : D. Summers, L. Cremaldi, R. Godang, S. Bracker Understanding the Matter-Antimatter Asymmetry of the Universe (page 32)

33 Heavy Neutral Higgs Bosons In MSSM, the heavy Higgs bosons are largely degenerate The Higgs boson cross section in s-channel: σ h ( s) = 4πΓ(h µ µ)γ(h X) = σ (s m 2 h )2 + m 2 h (Γh tot )2 s = (2 MeV ) ( ) ( R s 0.003% 100 GeV ) The resonances are clearly overlapping (separated by 1 GeV ) Muon Collider could separate out these states with energy resolution: R = 0.01% and R = 0.06% Understanding the Matter-Antimatter Asymmetry of the Universe (page 33)

34 LHC Detectors LHC: p p collisions with CM-energy s = 14 T ev CMS Collaboration: 2000 scientists with 155 institutes in 37 countries Search for Higgs is one of the main goals in CMS Search for Black Holes: M. Cavaglià, R. Godang, L Cremaldi, D. Summers Understanding the Matter-Antimatter Asymmetry of the Universe (page 34)

35 The CMS Experiment U. Miss: L. Cremaldi, R. Godang, R. Kroeger, D. Sanders, D. Summers Understanding the Matter-Antimatter Asymmetry of the Universe (page 35)

36 CATFISH: New MC Generator We introduce a new MC generator so called CATFISH CATFISH (Collider gravitational FIeld Simulator for black Holes) New features of CATFISH compared to other BH generators : CATFISH is more flexible and user friendly It includes different final BH decay modes with possibility of remnant formation It includes Graviton field emissivities CATFISH authors: M. Cavaglià, R. Godang, L. Cremaldi, D. Summers The paper has been submitted for a publication Understanding the Matter-Antimatter Asymmetry of the Universe (page 36)

37 CATFISH Website CATFISH is well documented and available for public Understanding the Matter-Antimatter Asymmetry of the Universe (page 37)

38 BH Events Shape in CATFISH BH events are expected to be highly spherical due to the spherical nature of Hawking evaporation process 10 5 Number of Events M = 1 TeV, n = 6 M min = 1 TeV n p = 2, BD n p = 4, BD n p = 2, YR n p = 4, YR Number of Events M = 1 TeV, n = 6 M min = 1 TeV n p = 2, BD n p = 4, BD n p = 2, YR n p = 4, YR Sphericity R 2 H 2 /H 0 Experimentally one needs to distinguish between BH events shape with q q events as BH-background (back-to-back events shape) (left) Sphericity BH events shape, S > 0.30 (depends on M min ) (right) Fox-Wolfram moment, R 2 < 0.50 Understanding the Matter-Antimatter Asymmetry of the Universe (page 38)

39 The Higgs Production at CMS H o production at hadron colliders: q g g g fusion : g t t t t H o q WW, ZZ fusion : q W,Z W,Z q H o g t t fusion : g t t t H o q q W,Z W, Z bremsstrahlung W,Z H o σ (pb) 10 gg H σ(pp H+X) s = 14 TeV m t = 175 GeV CTEQ4M qq Hqq 10-1 qq HW gg,qq Htt 10-3 M. Spira et al. gg,qq Hbb NLO QCD qq HZ M H (GeV) But : BR ( H Z Z 4l ) = BR ( H Z Z 4µ ) = events for 10 5 pb -1 D_D_1186.c Understanding the Matter-Antimatter Asymmetry of the Universe (page 39)

40 The Higgs Discovery at CMS The relative light Higgs mass M H < 120 GeV SM Higgs Branching ratios and total decay width For M H < 150 GeV, the most promising channel: 1 bb WW H 0 γγ (dominated by energy resolution) 10 1 τ + τ ZZ But the branching fraction is small BR(H) 10 2 cc gg tt The decay width is about few tens kev only ECAL performance is very crucial in this analysis We are working on ECAL and HCAL simulation (GFLASH): R. Kroeger and R. Godang Γ(H) [GeV] γγ Zγ M H [GeV] M H [GeV] D_D_ 2061 c Understanding the Matter-Antimatter Asymmetry of the Universe (page 40)

41 The Higgs Discovery at CMS... 3 channels cover Higgs mass range H 0 γγ H 0 Z 0 Z σ Higgs Signals (statistical errors only) LHC 14 TeV (SM NLO Cross Sections) H 0 W ± W We expected to have about 10 fb 1 data for 1 year running We hope to discover Discovery Luminosity [fb 1 ] 10 1 H γγ Standard Model Higgs in 2008? H ZZ H WW U. Miss proposed to measure D_D_1285c H 0 W + W, (W + W l + l ν ν) M Higgs [GeV] More data are needed to study the Higgs properties Understanding the Matter-Antimatter Asymmetry of the Universe (page 41)

42 Summary CP Violation in B system has been observed α = (92.1 ± 5.1) β = (24.6 ± 1.7) γ = (63.1 ± 5.0) Current precision of V ub and V cb measurements : ( V ub V ub ) = (3.3 exp ± 2.9 model ± 4.7 SF ± 4.0 th )% = 7.6% BABAR is aiming to measure ( V ub V ub ) = 5% ( V cb V cb ) = 2%. (Partial Reconstruction method will confirm this) Many interesting physics analyses are available at BABAR Search for Higgs and BH at LHC is underway Using CATFISH, we hope to discover mini BH production at CMS New discoveries are waiting to be explored at LHC! Understanding the Matter-Antimatter Asymmetry of the Universe (page 42)

43 Hopefully... Will the Higgs be discovered in 2008? T H A N K S! Understanding the Matter-Antimatter Asymmetry of the Universe (page 43)