CP Highlights: Circa 2005

Amarjit Soni

HET, BNL

(soni@bnl.gov)

………….

National Taiwan Univ.

6/23/05

Outline• Introduction: B-Factory + Lattice …help attain an imp. milestone ->

• Improved Searches for χBSM in the light of BF results:

Indirect Searches with theory input

Indirect Searches w/o theory input: Elements of a Pristine UT

Direct Searches:

Penguin dominated hadronic modes

Radiative B-decays

Null Tests

• K-UT

• NEDM

• TEDM

• Link with ν-Physics: Leptogenesis

• Summary

Atwood +Soni, CKMfit PLB’01

More sophisticated recent updates (CKMfitter,J.Charles et al ’04; Utfit M.Bona et al’05) with

similar numbers

Theory vs. Expt (’04)• Angle Theory Expt.

• Sin2β .70+-.10 .726+-.037

• α [98+-16]ο [103+-13]ο

• γ [60+-7]ο ~ [70+-30]ο

EXPT MEANS “DIRECT DETERMINATIONS”

- Most likely effect of any BSM-CP-odd phase on B-physics

is (from now on) a perturbation. …..A SIGNIFICANT CAVEAT

Important Lesson from the CKM-paradigm

• We know now that CKM-phase is O(1)• CP asymmetries in K-decays are at most (.001)• In charm decays CPV expected to be very small• In top physics asymmetries are completely

negligible• Only in B decays effects are O(1)• If there is BSM-CP-odd phase of O(1) it would be quite a coincidence if B’s are favored again

eta

Basic ADSMaximize direct CP by maximal interference:

CLA X DCBS ~ CLS X CBA

B-

K- D0

K- D0

CLA DCBS

CLSCBA K-{K + π -}

Vub/N[Vcb Vcd Vus]-1 ~ 0.7

QM amplitude for two interfering pathsξK is strong phase for B ->K D0; ξfi is for D0 -> fi

ξK fi = ξK + ξfi

For a given final state fi 3 unknowns: unmeasureable Br(B- ->K- D)=b(K); ξK

fi ; γ

Taming Direct CP

• #ofmodes D0(bar D0) #Obs #unknowns

• 1 2 3• 2 4 4• N 2N N+2

• 4 8 6• .• .• ad infintum• .

Some of the relevant (common)modes of D0 ,D0

Br CP 1) GLW: CPES (CBA/SCBS)

KS [π0,η,η’,ρ0,ω]; π+ π- …. Σ few% <~10%

2) GLS: CPNES (SCBS)

K* K, ρ + π- …. ~0.5% <~10%

3) ADS: CPNES(DCBS)

K+ (*) [π- , ρ - , a1 -….] O(10-3) O(1)

gamma from B->DK with 2-body D decays

δ & β from TDCP studies of B0->”K0” D0

[Atwood & AS, hep-ph/0206045, develop methods for model independent use of multi-body & inclusive modes]

• Related works: Gronau & London ’91; Branco, Lavoura & Silva, ’99; Kaiser & London ’01; Sanda’02;

Gronau,Grossman,Shumaher,Soffer and Zupan,hep-ph/0402055

I) Note δ=(β – α + π) = (2 β + γ); Note also that this is yet another (and even cleaner) method for β & of course also for γ. II) However, it is less efficient than either

B0 -> ψ KS or B+ ->”K+” D0

III) Asy: CPNES ~ 0.35 CPES ~ 0.75

Commonality of B+ , B0

Same decays of D0 are used in DIRCP in B+ decays as wellAs in TDCP in B0 ,allowing for info from charm factories &

And elsewhere to b recycled

Summary & outlook on (direct)γ

IV) With O(.4 ab-1 [NOW] ) γ ~ (69 +- 30)о

Attainable accuracy with O(2 ab-1 [`’08]) will

be appreciably faster than 1/sqrt(N) due to

the plethora of channels opening up

V) By ~ 2008, Expect δ γ ~ (2 to 5)ο

Vi)Ultimate precision O(.1%) that the theory offers will require SBF

I.Projections for direct determination of UT

• Now(.2/ab) 2/ab 10/ab ITE

Sin2φ1 .037 .015 .015(?) .001 α 13 4(?) 2(?) ~1(?)

γ(φ3) 20,10,10 5<->2 <1(? ) .05

Must strive for a pristine,direct determination ofAll 3 angles w/o theory assumptions to level of ITE.ITE should be the HOLY GRAIL-> SUPER-B is essential for this goal

DIRECT SEARCHES…illustrations

• Penguin dominated hadronic FS…

• Radiative B-decays

• Tests aglore

A tantalizing possibilty:

Signs of a BSM CP-odd phase in penguin dominated b ->s transitions?

Brief Recapitulation: Basic Idea

Dominant decay amp.has0 weak phase [just as in

B->ψKS] up to O(λ2)

J.Smith@CKM05

J. Smith@CKM05

WA ~ 2.7σ

Brief remarks on the old study(with London, PLB’97)

• Originally motivated by the thenCLEO discovery of• Huge inclusive (see Browder..) as well as exclusive• (see J. Smith…) Brs. into η’ • Suggest with Atwood(PLB97;PRL97) use of η’ Xs(d)

for search of NP via DIRCP as in SM expect very small• With London suggest use of MICP in [η’ ,

η ,π0,ρ0,ω,φ….]KS to test CKM-paradigm via sin2φ1(β)• Present simple (naïve) estimates of T/P …for all cases find, T/P <0.04• Due to obvious limitations of method suggest conservative

bound ΔSf <0.10 for the SM

For DIRCP see also Hou&Tseng,PRL’98

Glmpses from a few theoretical studies

• I. London &A.S.PLB’97…use naïve quark model to suggest

ΔS=0 + O(few%) for B->KS[ή,η,π,φ,ω,ρ…];but, in view of

hadronic uncertainties advocate ΔS>0.1 may be problematic

for the CKM-paradigm.Note, paper was basically motivated

by the huge Br of ή KS discovered @ CLEO

II 1) Mishima & Li (pQCD) KS[π,φ] very clean..[How about ή??]

• 2)Beneke&Neubert(hep-ph/0308039) use QCDF in

their study …main conclusion:

KS[ή,φ] are the cleanest modes with smallest ΔS & smallest

uncertainties

3)Cheng,Chua,A.S. [QCDF+FSI], KSή is cleanest; KSφ is

also very clean (hep-ph/0502235)

A possible complications: large FSI phases in 2-body B decays

• The original papers predicting ΔSf=Sf - SψK ~0used naïve factorization ideas; in particular FSIwere completely ignored.

A remarkable discovery of the past year is that directCP in charmless 2-body modes is very large->(LD)FS phases in B-decays need not be smallSINCE THESE ARE INHERENTLYNon-perturbative model dependence becomesunavoidable

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E x p t ( % ) Q C D F ( d e f a u l t ) Q C D F ( S 4 ) p Q C D

D C P V s i n s i n ( : w e a k p h a s e , : s t r o n g p h a s e )

Q C D F : Q C D f a c t o r i z a t i o n ( B e n e k e , B u c h a l l a , N e u b e r t , S a c h r a j d a1 9 9 9 )

p Q C D : b a s e d o n k T f a c t o r i z a t i o n t h e o r e m ( L i , K e u m , S a n d a )A s i z a b l e s t r o n g p h a s e f r o m p e n g u i n - i n d u c e d a n n i h i l a t i o n

Q C D F ( S 4 ) s c e n a r i o : l a r g e a n n i h i l a t i o n w i t h p h a s e c h o s e n s o t h a t a c o r r e c t s i g n o f A ( K + - ) i s p r o d u c e d ( A = 1 , A = - 5 5 f o r P P )

I t i s n a t u r a l t o c o n s i d e r L D s t r o n g p h a s e s i n d u c e d f r o m f i n a l - s t a t e i n t e r a c t i o n s

For penguin dominated modes,e.g (π,ω)KS

the subdominant tree is color suppressed, but FS rescattering phases arise from color

allowed tree so can have large effects

It is important

7

F S I a s r e s c a t t e r i n g o f i n t e r m e d i a t e t w o - b o d y s t a t e s

[ H Y C , C h u a , S o n i ]

F S I s v i a r e s o n a n c e s a r e a s s u m e d t o b e s u p p r e s s e d i n B d e c a y s d u e t o t h e l a c k o f r e s o n a n c e s a t e n e r g i e s c l o s e t o B m a s s .

F S I i s a s s u m e d t o b e d o m i n a t e d b y r e s c a t t e r i n g o f t w o - b o d y i n t e r m e d i a t e s t a t e s w i t h o n e p a r t i c l e e x c h a n g e i n t - c h a n n e l . I t s a b s o r p t i v e p a r t i s c o m p u t e d v i a o p t i c a l t h e o r e m :

i

ifTiBMfBMm )()( 2

• S t r o n g c o u p l i n g i s f i x e d o n s h e l l . F o r i n t e r m e d i a t e h e a v y m e s o n s ,

a p p l y H Q E T + C h P T ( f o r s o f t G o l d s t o n e b o s o n )

• F o r m f a c t o r o r c u t o f f m u s t b e i n t r o d u c e d a s e x c h a n g e d p a r t i c l e i s

o f f - s h e l l a n d f i n a l s t a t e s a r e h a r d

A l t e r n a t i v e : R e g g e t r a j e c t o r y [ N a r d u l l i , P h a m ] [ F a l k e t a l . ] [ D u e t a l . ] …

Cheng,Chua,A.S.Hep-ph/0502235

1.Note in SD, ΔS switches sign bet. ω,ρ for us no change2. LD rescattering effects on S & C are highly correlated and similarlyC’s of isospin partners are correlated -> many testable predictions,e.g

LARGE (13%)DIR CP for ω KS & HUGE for ρ KS (~ -46%)

ΔSf >0.10 would be a compelling evidence for BSM-CP odd phase!

Effects of FSI on penguin dominated modes(Cheng,Chua and AS)

Expectations for ΔS in the SMMode pQCD(SM ) QCDF(MB) QCDF+FSI(CCS)

η’KS .01(.01,-.01) .00(.00,-.04)

φKS ..020(.004,-.008) .02(.01,-.01) .03(.01,-.04)

πKS .009(.001,-.003) .07(.05,-.04) .04(.02,-.03)

HWT: η’Ks in pQCD?

J.Smith@SBF’05

Will answer thisLater in own way

C later

Averaging issue:Are we makinga mountain outa anthill?

• I am rather sceptical and concerned about

averaging over many small deviations,

leading to ~3.7 σ ….On the other hand,

London&A.S,hep-ph/9704277

Although, at the moment it is at best a marginal effect, it may well become a serious blunder on the part

of experimentalists to ignore it!We can try learn some lessons from history.

It is extremely important to understandthat basically it is a very good test of the SM and

theoretically it can be further improved

Christenson,Hicks,Lederman,Limon,Pope & ZavattiniPRD 8,2016 ‘72

<-`Leon’s shoulder

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P r o j e c t i o n s a r e s t a t i s t i c a l e r r o r s o n l y ; b u t s y s t e m a t i c e r r o r s a t f e w p e r c e n t l e v e l

L u m i n o s i t y e x p e c t a t i o n s

:

2 0 1 22 0 0 4

( ) 0 . 1 5S

S c a l e c h a n g e !

Macfarlane@SBF’05

M. Hazumi@CKM05

Can our theoretical understanding be improved?

YES!

• Improved measurements of Br and CP

[DIRECT AND MIXING INDUCED]

in related modes, such as [ή,φ,π…]K-(*)

can help greatly in improving model calculations

[EVEN THEORISTS CAN LEARN!]

What if improved measurements(e.g.) show ΔSήK>.20+-0.02

BOTTOMLINE

It is IMPOSSIBLE that genuine NP will show

up only in ή KS , many other hadronic (b ->s)

final states MUST show NP effects.

Furthermore, radiative and (pair)leptonic will in all likelihood be affected as well

B→γP1P2

• In this case there is potentially additional information from the angular distribution of the two mesons.

• There are two different cases of how the angular information enters

1) P1=P2 e.g. B0→π+π−γ. In this case the angular distribution gives you the information to calculate sin(2ψ) and sin(φL+φR+φM) separately.

2) P1 and P2 are C eigenstates e.g. B0→K sπ0γ. In this case you

can obtain no additional informaton from angular distributions but you can add all the statistics (as unlike AGS K pi need not be resonant) and thereby it allows a more stringent test for NP, that is, a more accurate value of the NP phase

• In both cases the variation with Eγ tests whether dipole

emission is an accurate model (see eq)

AG’HS (hep-ph/0410036)

Intutive elaboration of why/howAGHS idea works

In AGS eq.3, strong interaction (meaning leaving out weak phase) info is in (A sin ψ).For 3-body modes of AGHS interest, such quantities, in general,

become functions of Dalitz variables, s1 and cosΘ=z:

S1 = (p1 + p2)2 ; S2 = (p1 + k)2 ; S3 = (p2 + k)2

k is photon momentum, so z = ( S2 – S3)/ ( S2 +S3) .

Now for L,R helicities particle and antiparticle decays

we have 4 amplitudes so we have 4 such quantities now: fL , fR and similar 2 for anti-particle. Each is now a function of

s1 and z. But QCD respects P, C and therefore for ( I) the

case of Ks π0 all 4 become identically the same upto a sign.Thus time-dependent CP asymmetry A(t) becomes independent of Dalitz variables.

Expression for A(t) holds whether Ks π0 are resonant or not or from more than one resonance, in fact! Since A(t) is independent of s1 all points in Dalitz plot can be added. Significant improvement in statistics and in implementation. Combining the data together one gets significantly improved info on sin(ψ) sin(Φ) …the product of strong and weak phase which allows putting lower bound on each.

AGHS for π+ π- + gammaThis is the generalization for b -> d penguin of the rho gamma case…Since pi+ pi- are now antiparicles . Therefore, under C, S2 and S3 get interchanged and as a result z->-z.So angular distribution becomes non-trivial.Once again, resonant and non-resonant info can be combined but now additional angular info becomes available to allow a separate determination of the strong and the weak phase (up to dis. Ambig)!

Some Details• Usual Expt. Cuts to ensure underlying 2 body bs(d) + γ

is necessary…that is, HARD PHOTON…in particular to discriminate against Brehmms

• Departure from that will show up as smears around a central value on the Dalitz plot

• In principle, annhilation graph is a dangerous contamination, due to enhanced emission of (LD) photons off of light (initial) quark leg (see Atwood,Blok and A.S). This is relevant only to b ->d case. Fortunately,can prove that these photons have have same helicity as from the penguin. See AGHS for details.

Implications for B -> K ή γ of AGH’S

• AGH’S not only allows K π γ from allKaonic resonances (irrespective of JCP) as well as from non-

resonant continuum to be included even a more important repercussion

off AGH’S is that K ή γ can be used. This is significant as Br(K ή)/Br(K π) ~ 7For these reasons expect AG’HS to allow improvement over

AGS (resonance only) by factor O(2-5) so that with current O(108.5) luminosities

asymmetries O(0.20) may become accessible. With 1010 B’s may be able to get down to O(few%)

Dealing with Theoretical subtelties• QCD corrections introduce complications (though don’t expect 0.1)….Asy(S) becomes function of inv.

mass,angle,final state, whereas all 3 collapse into a single constant for LO analysis; schematically:• dSi/dMdZ = A0 + Bi +Ci M+ DiZ

where I=γ[K*, K,2*,K3*….;K π(η’,η)…]• That is now HW for the exptalists …do MC• Important point is that INTERPERTATION IS DATA DRIVEN

It would be useful to theoretically compute the coeff. For exclusive FS.

• These are radiative NOT hadronic final states.• Therefore calculations significantly less difficult than exclusive• Hadonic FS• Should be amenable to pQCD, QCDF, SCET….

Hierarchy of CP asymmetries in radiative B-decays

MIXCP DIRCP

b->s O(λ2) ~ 3% 0.6%

b->d O(.1%) O(15%)

April 20, 2005 Super BABAR Status & Plans 34

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PEP- I I , KEKB Super B- Factory 10/2011

SuperB

MacFarlane@SBF’05

Browder&A.S,hep-ph/0410192

Approximate Null Tests (Ants)Aglore

Direct Searches

K-Unitarity Triangle

• There is considerable interest in constructing the• UT purely from K-decays…relevant reactions being• pursued:

• Indirect CP violation parameter ε with BK from lattice

• K+ ->π+ υ υ can give clean Vtd

• KL ->π0 υ υ can give super-clean η (expt. very challenging)

• Direct CP ε’ with lattice matrix elements (theo. Very• Challenging)

Neutron EDM: a classic “null” test• In the SM NEDM cannot arise at least to two• loops in EW……..expect < 10-31 ecm• Long series of experiments now place• a 90% CL bound, <6.3 X 10-26 ecm (Harris et

• al, ’99)• In numerous BSM, including SUSY, Warped• extra-dimensions, …… neutron edm close• to current bound is expected

Top quark EDM: a clean “null” test

• Top is so heavy compared to other quarks that

GIM mechanism is super-effective -> all SM

CP violation effects are vanishingly small.

• As one concrete illustration is the top quark

Electric dipole moment….In the SM you need to

go to 2 loops in EW

Expectations for top quark edm in SM & Beyond

Atwood, Bar-Shalom,Eilam & Soni, Physics Reports:CP Violation in top quark physics

Search for BSM CP violation in top physics is an importantgoal of the International Linear Collider

Summary (1 of 2)

• Spectacular success of B-factories -> milestone in our understanding of CP violation: CKM-paradigm is confirmed. • Direct measurements of β agree remarkably with theoretical expectations to about 10% ; so also the 1st relatively crude measurements of α and γ ->any beyond SM CP-odd phase likely to cause a small perturbation in B-physics…..Likely to require lots and lots of clean B-samples and super clean

predictions from theory to search BSM phase

Summary (2)• In particular, we know now how to determine γ and α also (β was already known) to accuracy of better than O(1%)….this will require 1010 B’s, some 20 times more than current luminosities but is extremely well motivated• Penguin dominated hadron FS, much in the news but for now no convincing “deviation” from SM; However, it is a powerful test and its extremely important to reduce errors to O(5%) …may well need a SBF• K-UT, NEDM, TEDM…need be pursued with renewed

vigor in search for new sources of CP-odd phase(s)