Introduction Results CP Symmetry in Particle Exp. method ... · CP Symmetry in Particle Physics Introduction Results B-Factory Interpretation Exp. method Future Boštjan Golob Faculty

CP Symmetry in Particle Physics

Introduction Results

B-Factory Interpretation

Exp. method Future

Boštjan GolobFaculty of Mathematics and Physics

Jožef Stefan Institute Belle/Belle II Collaboration Introduction

B-Factory

University of Ljubljana

“Jožef Stefan” Institute

Exp. method

ResultsResults

Interpretation

Physics in Ljubljana Summer School, Ljubljana, July 2011

Future

Quest for New Physics

B. Golob 1/19Physics in Ljubljana, FMF, July 2011

j j y y

Introduction

Why CP (A)Symmetry?

Introduction ResultsB-Factory Interpretation

Exp. method Future

y ( ) y y

The amount of matter (particles) and anti-matter (anti-particles) in th l U i th

considering baryons (like protons): Nb-Nb = 0the early Universe was the same;

Nowadays (at least “near”) Universe (~ 10 Mpc; 1 Mpc = 3 3 106 light years)

Nb Nb 0initial state of Universe

(~ 10 Mpc; 1 Mpc = 3,3⋅106 light years)consist of matter;

During the evolution of Universe baryons

experimental determination(e.g. AMS experiment):

NNNNDuring the evolution of Universe baryonsannihilated into photons

b + b → γ910 1010 −− −=

=+−

=−

bb

bbbb

NNNN

NNN

γ

γNγ ∼ Nb + Nb(Microwave Cosmic Background) In the Universe today particles

completely dominate over


Why all anti-baryons annihilated, while 1/109 baryons did not?

p yanti-particles

Introduction

Why CP (A)Symmetry?


Exp. method Future

y ( ) y y

A. Saharov, 1967: necessary conditions for the evolution f t i U i ( tt d i t

C: charge conjugation operator

C|X> = ± |X>of asymmetric Universe (matter dominates over anti-matter):- baryon number violation,

thermal non equilibrium

P: parity operator

P|X> = ± |X>- thermal non-equilibrium, - CP and C symmetry violation (CPV)

P|X> = ± |X>

CPV: physical processes are not equal when spatial CPV is necessary condition

f

CPV: decays of particles proceed slightly differently than decays of anti-particles

coordinates are inverted and particles are exchanged by anti-particles

for matter dominated universe

y y p

B+

K+

π+B-π-

π+

CP


π+

π- K-CP

Introduction

Why CP (A)Symmetry?


Exp. method Future

y ( ) y y

CPV can be studied with elementary particles

mesons: particles composed of q and q’B mesons: mesons composed of b and q’

CPV discovered in 1964 in decays of neutral kaons (Nobel prize James Cronin Val Fitch 1980)

mesons composed of b and q

meson quarkiti

mass(G V/ 2)

lifetime

James Cronin, Val Fitch 1980)

Since 1999: precise measurements with B mesons to understand composition (GeV/c2)

B0 bd 5.28 1.54 ps

B- bu 5.28 1.67 ps

with B mesons to understand the underlying principle

=> B meson “factories”

B0 bd 5.28 1.54 ps

B+ bu 5.28 1.67 ps


p

B-Factory

Accelerator KEKB:KEKB:


Exp. method Future

Tokyo (40 mins by Tsukuba Exps)“BB--Factory”,Factory”, KEKB @ KEK

e- (HER): 8.0 GeVe+ (LER): 3.5 GeV

ECMS=M(Υ(4S))c2

e-

e+b

bu,d

b

bΥ(4S)

Bd0, B+

e bu,d

Bd0, B-

e+e- → Υ(4S) → Bd0Bd

0, B+B-Copious production of B mesons possible at “B-Factories”


(from 1999 - 2010 ~109 BB pairs)

B-Factory

Detector Belle


Exp. method Future

Central Drift Chamber e+

3(4) layerSi det.

3.5 GeV

AerogelCherenkov

e-

8 GeV

(n=1.015-1.030)

1.5T SC solenoid

EM calorimeterCsI (16X )

µ and KLCounter(14/15 layersRPC+Fe) CsI (16X0)RPC Fe)

Various detector modules to determine - charged particles momenta, energy, id (pions, kaons, protons, electrons,...)


g p , gy, (p , , p , , )- neutral particles energy, id (γ, neutral kaons, neutral pions...)- common decay points of various final state particles from B meson decays

Exp. method

Method of (one of) mesurementsMethod of (one of) mesurements particles detectedi d t t


Exp. method Future

e od o (o e o ) esu e e se od o (o e o ) esu e e s in detectorshort-lived particles not directly detected

B i

J/ψ

µ+

µ-

π-

Fully reconstructed B decayinto CP eigenstate (B0 or B0

can decay to it) T i f

B0 or B0

Bsig

Btag

Ks π+

K-l -

Tagging ofother B flavor

from thecharge∆t=∆z/βγc

Υ(4

s)

gof typical

decayproducts

∆t=∆z/βγcdeterminedB0(B0) ∆z ~ 100µm

Determination of the time between decays of two B’s


Exp. methodIntroduction ResultsB-Factory Interpretation

Exp. method Future

∆t distribution for Υ(4S) → B0 B0 → (e.g. J/ψ Ks) (Xtag):

q = ± 1: Btag = B0, B0 Sf ≠ 0: time dependent CP violation (TCPV)Af ≠ 0: time independent CP violation (DCPV)∆md: B0B0 oscillation freq. f p ( )∆md: B B oscillation freq.

Why Sf ≠ 0, Af ≠ 0 means CPV?

)()( 00 BBtBBt ∆∆ PP)cos()sin(

);();();();(

00

00

tmtmBBtBBtBBtBBt

A fftagtag

tagtagCP ∆∆+∆∆=

=∆+=∆

=∆−=∆= AS

PPPP


Quantities determining difference between B0 and B0 can be measured

Results

Btag=B0ResultsResults one quantity related to CPV in system of B mesons


Exp. method Future

Belle PRD66 032007 (2002)

Btag BBtag=B0

ResultsResults in system of B mesons measured with a great precision

Belle, PRD66, 032007 (2002)

significant measurement of CPV in B0 system;exp. evidence that CPV is indeed intrinsic property of weak interaction (CPV in K0 - 1964)property of weak interaction (CPV in K 1964)

Sf =0.99 ± 0.14 ± 0.06

Belle, PRL98, 031802 (2008)

Sf =0.642 ± 0.031 ± 0.017A

Sf,1999-2010:from free parameter of SM to precision measurement with accuracy ±3% (world

ACP


measurement with accuracy ±3% (world average)

Interpretation

CP symmetry among particles (Standard Model):


Exp. method Future

CP symmetry among particles (Standard Model):

KobayashiKobayashi--MaskawaMaskawa mechanism: mechanism: Carrier of weak interaction

Vud Vus VubV V V

W+qi

qV

Cabibbo-Kobayashi-Maskawa(CKM) matrix

XVcd Vcs VcbVtd Vts Vtb

qjVij(CKM) matrix

M. Kobayashi, T. Maskawa, Prog.Th.Phys.49, 652 (1973) (6140 citations) A(X →qiqj) ∝Vij

W-qi

if Vij=Vij* ► SM Lagrangian L =LCP ►

CP symmetry is conserved X

qjV*ijif elements of CKM matrix

complex ⇒ CPV

X

A(X →qiqj) ∝Vij*


A(X →qiqj) Vij

Interpretation

Basic motivation


Exp. method Future

V V V c12c13 s12c13 s13e-iφ

KobayashiKobayashi--Maskawa mechanism: Maskawa mechanism: can be parametrizedb 4 l tVud Vus Vub

Vcd Vcs VcbVtd Vts Vtb

c12c13 s12c13 s13e φ

-s12c23 c12c23 s23

s12s23-c12c23s13eiφ -c12s23 c23c13

=by 4 real parameters: 3 angles and one complex phase

All various observables related to CPV (not only the example

sij = sinθij, cij = cosθij

a ous obse ab es e ated to C ( ot o y t e e a p eshown in previous slides) can be related to the complex phase of CKM matrix

perform measurements of different observablesperform measurements of different observables ⇒ check if results agree with predictions of

Kobayashi-Maskawa model By performing measurement of various CPV observables Kobayashi Maskawa mechanism


Kobayashi-Maskawa mechanismcan be tested

Interpretation

Maj 1999 Maj 1999 -- July 2010July 2010 φ3, Dalitzl i


Exp. method Future

X(3872)

Belle, PRD73, 112009(2006) 48 citations

analysis

Belle, PRL103, 171801 (2009) 44 citations

B → K*l+l-

Belle, PRD68, 012001 (2003) 92 citations

TCPV, B0 → π+π- φ2


X(3872)

Belle, PRL103, 241801

B+ → Xs γ

(2009) 44 citations

(2003) 92 citations

Belle, PRL91, 261602

TCPV, B0 → φKS, K+K-KS, η’KS, sin(2φ1

eff) DCPV difference, B0 → K+π- in B+ → K+π0

, ,(2009) 15 citations

Belle, PRD66, 032007 (2002) 96 i i

TCPV, sin(2φ1)

, ,(2003) 145 citations

D0 mixing

Belle, Nature, 452, 332 (2008) 63 citations

(2002) 96 citations

B ll PRL93 021601 B+ → τ+ν



Belle, PRL93, 021601 (2004) 117 citatovBelle, PRL93, 191802 (2004) 137 citatov

DCPV, B0 → π+π-, K+π-


B → τ ν

Interpretation

Verification of Kobayashi-Maskawa mechanism


Exp. method Future

y

Perhaps most valuable confirmation of the importance of B-factories (Belle + BaBar) measurements:

2008

“During the past decade, elementary particle physicists have measured K b hi d M k ' th

2008

Kobayashi and Maskawa's theory with great precision and found that it really does fit the data.”

L. Brink, 2008 Nobel Prizet ti hpresentation speech

KEKB/BelleMay 1999 May 1999 -- July 2010July 2010


KEKB accelerator control room, July 2010: director general of KEK pressed the beam abort button of KEKB for the last time ⇒ SuperKEKB

Future

KobayashiKobayashi--Maskawa mechanism: Maskawa mechanism:


Exp. method Future

CPV as measured can explain baryon asymmetry of the Universeof smaller magnitude than observed

yy

d t

1610~ −

+−

BB

BB

NNNN

910 1010 −−− BB NNgand not

CPV as observed nowadaysis too small to explain the matter asymmetry of the universe

1010 −=+ BB

B

NN

while most of measurements agree with SM predictions, there are measured

matter asymmetry of the universe

uB+ τ+W+

discrepancies at the level of few standard deviationsexample:

b ν(H+)

410)34.064.1()( −+ ⋅±=→τνBBB(B → τν): contribution of charged Higgs

boson (in Minimal SuypersymmetricStandard Model)

Heavy Flavor Averaging Group,http://www.slac.stanford.edu/xorg/hfag/

)()(

410)76.0()( 06011.0 −+ ⋅±=→τνBSMB


CKMFitter, http://ckmfitter.in2p3.fr/

10)76.0()( 06.0±→τνBBcontribution of NP can have observable effect in rare processes within the SM

Future

Way to proceed?


Exp. method Future

y p

Kobayashi-Maskawa mechanism confirmed with accuracy available from existing B-factories;existing B factories;

hints of SM breakdown require at least one order of magnitude better accuracy;

σ ∝1/√N ⇒ O(102) higher luminosity

BeyondBeyondStandardModel

Belle II experiment will search for unknown particles and processes with unprecedented precision


with unprecedented precision

Quest for NP

High energy/high precision


Exp. method Future

Two complementary approachesTwo complementary approaches

high energy frontier high precision frontierAtlas, LHC

Belle II, SuperKEKB, p

figures approx. to scale

Search for production of unknown particles at highest achievable energies

Search for effect of unknown particleson processes very rare within the SM


particles at highest achievable energiesLHC

on processes very rare within the SMSuperKEKB

Quest for NP

LHC Operation and PlansLHC Operation and Plans


Exp. method Future

p - p collisions at largest attainable energies

produce so far unknown particles in these

pp

produce so far unknown particles in these collisions

Current status: LHC operation progressing better than planed.★High energy proton proton collisions at 7 TeV★Pb Pb heavy ion collisions at 2.76 TeV.Target is to collect Li t ~ 2 3 fb-1 of proton dataTarget is to collect Lint ~ 2-3 fb 1 of proton data by the end of 2011.Then technical stop in 2012 with upgrade/repair.In 2013 the LHC will ramp up to 14 TeVcentre-of-mass energy start collecting statistics with a high rate with Lint ~ 10 fb-1 by the end of the year

Ncoll = Lint x σ


Quest for NP

LHC Operation and PlansLHC Operation and Plans SM Higgs discovery potential at 14 TeV


Exp. method Future

Example: Search for Higgs boson

pp

in SM Lagrangian terms related to masses of all particles require the existence of H;

not yet observed experimentally;

search for produced Higgs bosons at LHC in various decay modesin various decay modes

example of H reconstruction when decaying to γ γ which are detected in Atlas detectorIf Standard Model Higgs exists, ATLAS will find it... Same holds for possible supersymmetric


Same holds for possible supersymmetricparticles, etc.

Particle physics at FMF

SummarySummary


Exp. method Future

Staff at FMF take part in the world-wide cutting edge research

yy

Some expert courses(2nd cycle degree):

in both experimental and theoretical particle physics

N t iti f

Nuclei, quarks, leptons

Advanced particle detectors and d t iNumerous opportunities for

international research work during studies, detector development & data analyisis (Master PhD thesis)

data processing

Experimental physics of elementary particles and nuclei& data analyisis (Master, PhD thesis)

Courses to lead your way in particle (and general) physics

y p

Quantum field theory

Theory of elementary particles( g ) y

Theory of elementary particles and nuclei

Gauge field theory


g y

....

Documents

Introduction Results CP Symmetry in Particle Exp. method ... · CP Symmetry in Particle Physics Introduction Results B-Factory Interpretation Exp. method Future Boštjan Golob Faculty