ants@bnmii (nara) soni1 ants @ a sbf bnmii, nara,dec18-19,’06 amarjit soni het, bnl [email protected]...

ANTs@BNMII (NARA) Soni 1

ANTs @ a SBFBNMII, NARA,dec18-19,’06

Amarjit Soni HET, BNL

[email protected]

Based on work with Tim Gershon hep-ph/0607230

mailto:[email protected]


Outline

• Introduction…In light of B-factories…the need for high luminosity

• New and some old ANTs

• Summary


The need for high luminosity in light of B-Factory Results.

• Spectacular performance of the B-factories• Allowed us to attain an important milestone in

understanding CPV phenomena• For the 1st time we have a striking confirmation of

the CKM-paradigm….(emerging picture since Feb. 2001)

However,NONE of our tests is good enough to exclude O(10%) deviations due BSM


Should 10% tests be good enough? Vital Lessons from our past

• LESSON # 1: Remember εK

• Its extremely important to reflect on the severe and tragic consequences ifCronin et al had decided in 1963 that O(10%) searches for ε were good enough!Imagine what an utter disaster for our field that would have been. Note also even though CKM-CP-odd phase is O(1) (as we now know)in the SM due to this O(1) phase only in B-physics we saw large effects…in K (miniscule), D(very small), t(utterly negligible).

Understanding the fundamental SM parameters to accuracy only of O(10%) would leave us extremely vulnerable …..Improvement of our understanding should be our crucial HOLY GRAIL!


Lesson #2

Remember mν

Just as there was never any good reason for mν =0 there is none for BSM-CP-odd phase not to exist

Δm2 ~1eV2 ~ 1980 -> Δm2 ~10-4 eV2 …’97

Osc. Discovered….

Similarly for BSM-CP-odd phase, we may need to look for much smaller deviations than the current O(10%)


The need for high luminosity

• (Arguments & Rationale NOT based on “SUSY” or its ghosts “around the corner”) but

Rather on “Key BENCHMARK Processes”:

• I) Pristine determination of UT..,

• γ(φ3) from {“B KD”; “BsKD”};

• α(φ2) from {π π, ρπ, ρρ}and β(φ1) from “ΨKs”

• II) Approx. Null Tests (ANTs); some specific examples

• aCP (B -> Xs(d) γ)

• S(t) {B -> [K* ,K π…] γ}

• S(t) {B -> KS [ η’ , φ….]}

• aCP (trans. Pol) {B -> XC(D) τ ν…..


In light of B-factories results:ANTs of SM become very important

Main message from B-factories:SM-CKM paradigm is the dominant contributor to the observed CPV effects of

NP are likely to be a small perturbation -> To fecilitate search for NP need:1. Precise predictions from theory2. Lots2 of clean B’sNULL tests ( i.e SM predicts vanishingly small asymmetries) are a very important class of precision tests. Since CP is not a symmetry of the SM cannot ( i.e. extremely difficult) have EXACT null tests…-> approximate null tests (ANTs) e.g. ΔS = S[B->ή(Φ..)KS] – S[B ->ψKS] ~O(λ2) an

ANT that’s recently much in news as BABAR+BELLE indicate a violation atabout 2 σ. Its confirmation is exceedingly important…Motivates us to develop additional null tests that are as strict as possible.


Some Examples of null tests


I. The incredible power of Radiative B’s 1) Rate for b -> s …over a decade of constrainig NP!

2) Rate for b -> d (excl. and incl.) for |Vtd|/Vts|

3) Dir CP b ->s and b ->d in SM and extensions; valueable tests of SM

4) Mixing induced & dir. CP clean tests of SM using exclusive B-decays…

a) ags(97)…B -> V γ

b) aghsI…B -> P1 P2 γ ;enhanced sensitivity to NP

c) aghsII…B->PVγ; SM pollution drastically reduced


Br(B ->Xs γ ) Confronts BSM

Expt (3.55+-.24+-.10+-.03)X10-4 …BaBar+Belle(HFAG) @ICHEP06

SM NLO (3.61+ .37-.49)X10-4 …T.Hurth Review

Excellent agreement has become extremely effective

in chopping parameter space of SUSY as well as multitude of other extensions.

Further improvement in SM prediction exceedingly

difficult…..-> Improved expt determination of

this Br per se provides limited mileage. However…


Direct CP-asymmetry• As testing the SM with measurement of inclusive Br is now

becoming less effective improved determination of the (inclusive) direct CP asymmery is gaining in sensitivity. Recall, in the SM,

• ACP (B -> Xs γ) ~ 0.6% …….SM• BaBar (89X106 ) =0.025+-0.05+-0.015• Belle (152X106 ) =0.002+-0.05+-0.030• -> Precise measurement & test of SM, most likely,• will require > 109 B’s. • With improved measurement of ACP (B -> Xs γ) should provide powerful (perhaps even better than Br) constrain on NP models.


ACP (B -> Xd γ)

• Expected to be much bigger (opp. sign)

In principle may be accessible with fewer

# of B’s as # of B’s needed scales

~ Br/(ACP )2


t


ACP (B -> Xd+s γ)• This is yet another powerful test of the SM-CKM-paradigm… is an excellent NULL TEST …i.e. SM predicts essentially 0 asymmetry.• First noted by J.Soares (’91) and later emphasized by Hurth & Mannel(’01) • BaBar (~90X106 B’s), hep-ex/0507001 ACP (B -> Xd+s γ) = -.110 +-.115 +- .017• All three dir. CP asymmetries are extremely powerful in constraining NP models.


Salvaging exclusive modes forprecision tests• Prior to ~97, exclusive modes remain unexploited for precision tests…

• This is quite unfortunate as experimentally exclusive modes are far more straightforward compared to inclusive ones

• Precision tests of the SM using time dependent or direct CP involving

• I. B0 -> K*(ρ) γ…, Atwood,Gronau and A.S.;PRL’97

• II. B0 -> {KSπ0(η’,η),ππ…}γ; Atwood,Gershon,Hazumi & AS, PRD’05

• III B+-0,Bs ->{Kφ(ω,ρ),η’(π) φ(ω,ρ), .…}γ; Atwood,Gershon, Hazumi & AS… (See BNL-HET-06/15 to be submitted)


Limitation of inclusive measurements

• Though inclusive Br (B->Xs γ)measurement provides an excellent test of the SM (now to

~10% accuracy), it is rather insensitive to testing the presence of “forbidden” helicity (i.e. RH photons in b-quark decays)…• {This is because rate monitors the incoherent sum of LH & RH}• Monitoring polarization of the photon is crucial…• THIS IS WHERE heretofore unexploited exclusive radiative decays come in handy.


Dealing with the higher order corrections

• Practically decade after AGS’97observation, Grinstein,

Grossman, Ligeti and Pirjol (PRD’05), examined higher order

corrections and identfied a potentially important source

for “wrong” helicity photons


higher order corrections• Their (SCET) analysis,confirming earlier work, showed

these corrections are 1/mb suppressed. Grinstein and Pirjol did a dimensional analysis (not an actual computation of the ME), PRD’06, suggesting corrections could be rather sizeable, rendering,

• S(t)~ sin2φ1 X O(0.1). Since an extra gluon is involved it requires either suppression also by αs (hard glue) or participation by (suppressed) higher Fock states…..

THEREFORE IN ALL LIKELIHOOD,GP’s RESULTIS A GENEROUS OVERESTIMATE


EXPLICIT CALCULATIONS• Already two very important explicit computations of these higher

order corrections have recently become available:• I. M.Matsumori and A. I. Sanda, PRD’06 use pQCD and find S(t) = (3.5+-1.7)%II. P. Ball and R. Zwicky, hep-ph/0609037,In another very commendable study use QCDSR and find

S(t)=[2.2+-1.2(+0-1)]% BOTH THESE STUDIES SHOW GRINSTEIN et al.CORRECTION IS ACTUALLY VERY SMALL and theylargely substantiate original AGS estimate confirming the

cleanliness of this test of the SM


Important Generalizations to AGS• I. B0 -> {KSπ0(η’,η),ππ…}γ; Atwood,Gershon,Hazumi &AS, PRD’05. Not

on only this is a very important genralization to AGS, It also develops a DATA DRIVEN method for separating (unwanted) effects of higher order corrections ….thus their rendering their precise numerical value quite

irrelevant

• II B+-0,Bs ->{Kφ(ω,ρ),η’(π) φ(ω,ρ), .…}γ; Atwood,Gershon, Hazumi and AS…WIP

• This generalization is now to FS that are VECTOR + Scalar (+photon)…Presence of the vector enhances the sensitivity to NP significantly and renders it essentially a PERFECT NULL TEST..(i.e. SM pollution virtually zero


Current experimental status & outlook for the future

• S (K*γ) = -.32+-.36+-.05 Belle (535M B’s)

• -.21+-.40+-.05 BaBar (232M B’s)

• HFAG -0.28 +-.26

• SUPER-B Projections by BABAR & BELLE:

• Luminos. 1035 -> S ~0.07

• 8X1035 -> S~ 0.03


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.


Intuitive 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- + γThis 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

dominantly have same helicity as from the penguin. See AGHS for details.


So far

• I. K^* gamma….K^**, K_2… (AGS)• NOTE THAT ITSELF HAS a handle for seprating SM

``pollution” from NP since to the extent LOHeff is valid, irrespective of mass of the resonance or its JCP, S(t)

• Should all be the same….Dispersion among them is in fact a {data driven} monior of HOC

• II. K^0 pi^0 {eta, eta’, pi^0…) gamma Once again there is a data driven handle for that separation as

irrespective of phton energy or of the MM’γ FS, S(t) should be the same…Allows improved

statistics & again dispersion in S(t) is a measure of importance of HOC

• III. Generalize to PVgamma


New physics signals in B->PVγ(e.g.ΦKγ)

• Presence of a Vector in the FS allows many

useful observables to be constructed,

in particular, triple correlations.

• A highly distinctive FS : B+- ->ΦK+- γ ;(Φ-> K+K-)

• Sizeable BR : (3.4+-0.9+-0.4)X10-6; see A.Drutskoy et al

(Belle), PRL ’04 {Used 90M B’s}

Babar {hep-ex/0607037; 207M B’s} also finds: I. Br (B+-) =[3.46+-.57+-.39] X10-6

II. ACP (B+-) =[-26.4+-14.3+-4.8]% ….NEEDS ATTENTION

III. Br(B0) <2.71 X10-6


Rich plethora of measureable observables in B->PVγ


The general form of the angular disribution


Null tested perfected: GOLDEN OBSERVABLE

• sinΦ terms in angular disribution are CP-odd,

TN odd (so don’t require absorptive phase)…

They go as ~ (CP-odd phase)XFR /FL

SM…CP odd phase is in b ->s penguin ~O(λ2)

SM…. FR /FL ~{ms/mb + hoc}• THUS dir CPV triple co-or is reduced to about 1/20 previous (already suppressed)! TDCP asy in K* γ……..i.e. well below 1%• TRIPLE COR. Asy (TCA) in ΦKγ is an extremely clean null test

of the SM

• For more details see Atwood, Gershon,Hazumi&AS

(to be published)


LOGIC

• I. LOOK for TRIPLE CORR

• II. IF YES LOOK FOR P-odd C_even TCA

• III. MAY Also be useful to

adopt (flavor) untagged analysis

Specific example of U-spin related modes:

B+ -> pi+ (K+) K0* gamma

B+ -> rho+ (K*+) K0 gamma


Summary on radiative decays• Radiative B-decays one of the most important FS for exploring new

phenomena • Though Br(B->Xs γ) unlikely to payoff more, precise determination of CP-

asy (B->Xs γ), Br(B->Xd γ), CPA (B->Xd γ),CPA (B->Xs+d γ), are vitally important goals • TDCPA in B-> γ(K* ; K1 ; K2..; KS π(η,η’)..ρ,ρ’..π π..) &TCA in

γΦ(ω,ρ)K..and many other VPγ provide very clean null tests of the SM & verypowerful probes of NP at the SBF…

• In particular, now also use dir CP for extremely precise tests of SM • Some of the FS MAY also be doable in an

hadronic environment.


II.A class of semi-inclusive hadronic B-decays as null tests of the SM

Jure Zupan & A.S. (hep-ph/0510325)• SM-CKM paradigm predicts completely

negligible partial width diff &CP Asymmetry

in B+- -> M 0(M0 )Xs+d+- where M0 is either

1) An e.s. of s<->d switching symmetry; e.g

KS , KL , ή, any charmonium state

2) If M0 & M0 are related by s<->d transformation, e.g.

K0 , K0* , D0 , ψ


Some Remarks

• These are precision null tests wherein the PWD

or the CP asy. Suffer from double suppression,

i.e. CKM unitarity constraints~O(λ2) and U-spin

symmetry of QCD ~O(ms /Λ QCD )

(As mentioned earlier, the corresponding radiative case studied extensively by Hurth and Mannel; see also Soares)


Numerical estimates

M0 ACP(d+s)

D0 + D0 O(0.1%)

ή O(0.1%)

K0 O(0.04%)Asymmetries are all a lot less than 1%Stress that motivation for going after ANTs is that alongthe way you are likely to find NP………


Remarks relevant to expts.

• These tests are semi-inclusive …; also no time dependent measurements are needed.

Since M0 takes about ½ the energy, the hadron complex X has only about ~2-2.5GeV available energy…so it should hadronize into relatively low multiplicity events…This should help in the strategy where the inclusive state is built by a sum of exclusive modes.

• At the SuperB one may use the alternate approach of fully inclusive analysis on the recoil. This requires reconstruction of one B and then M0 is searched in the remaining event. Assuming an efficiency for reconstruction same as the B-factories, around 10-3 , sensitivity to

asymmetry of 1% requires over 1011 B’s…..• While this may appear daunting, it is important to remember,

here and below throughout, that the key point about these precision ANTs is that along the way one may find signs of EXOTICA!


Recent development

hep-ph/0607053


A tantalizing possibilty:

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

III


1 with penguinsFrom Masashi Hazumi


ICHEP2006: 1 with b s Penguins

Smaller than bccs in all of 9 modes

Smaller than bccs in all of 9 modes

Theory tends to predictpositive shifts(originating from phasein Vts)

Naïve average of all b s modes

sin2eff = 0.52 ± 0.052.6 deviation betweenpenguin and tree (b s) (b c)

Naïve average of all b s modes

sin2eff = 0.52 ± 0.052.6 deviation betweenpenguin and tree (b s) (b c)

More statistics crucial for mode-by-mode studies


φKs also very clean in pQCD {0.020+0.008-0.004}, see Mishima & Li


Some More on ΔS

• ΔS REMAINS an EXCELLENT TEST• Sign of ΔS theoretically NOT reliable (in model calculations small central value

with rather large errors…see also Williamson&Zupan for η’K negative)

• CONCLUSIVE evidence for NP demands |ΔS| >0.10 IN EACH of several of the CLEAN modes


A Rigorous Sum-Rule FOR EWPFor π K modes:

2Δ(π0 K+ ) - Δ(π+ K0 ) -Δ(π- K+ ) +2Δ(π0 K0 ) =0Δ=PARTIAL WIDTH DIFF.Assumes only isospin; therefore, rigorouslymeasures EWP…see Atwood and A.S. PRD’98Note asymmetries ~20% were discussed.Not everyone is surprised by this muchDiRCP…It does introduce subtleties that we need to

disentangle

IV. Are the EWP too fat?

See also Lipkin (hep-ph/9810351; Gronau (hep-ph/0508047)


Dir CP in B+ -> π+π0 an important `null’ test

π+π0 is I=2 final state so receives no contribution from QCDP and only from EWP + tree (of course)

SM provides negligibly small (less than

about 1%) asymmetry even after including

rescattering effectsEspecially sensitive to NP and should be exploited

Similarly ρ+ ρ 0

see CCS for details

Are the EWP too fat?

Expt. Prospects Now 2/ab 50/ab

.01(.06) .03 ~.006

V

See cheng,chua&AS,Hep-ph/0409317


VI:

A verystringentNull test


0.1%

Need over 5X1010 B’s


*

*

ANTs @ a SBF

Gershon &AS,hep-ph/060230; c also,Browder & AS, hep-ph/0410192


Remarks

• In some instances, even though getting to SM test may seem very demanding, it is useful to stress again that along the way one has ample opportunity to detect contributions from EXOTICA


Summary & Conclusions (1 of 2)• While there is compelling theoretical rationale for a BSM-

CP-odd phase, in light of B-factories results, its effects on B-physics likely to be small -> Null tests highly desirable …discussed several of them

Power & Beauty of the SBF is it offers a HUGE ARRAY of Null Tests ….Not only these are sensitive to NP, measurements should

allow to discriminate between the models.

-> NEED SBF WITH ~1011 of clean B’sIn addition provides a unique opportunity for

SPECTACULAR τ, c phys


Summary & Conclusion

• SBF …extremely well motivated

• It COMPLMENTS LHC and in fact extend its reach greatly.

• Health & vitality of the field strongly suggests we seek a new, high lumin.

e+ e- B-facility as expediously as possible

ants@bnmii (nara) soni1 ants @ a sbf bnmii, nara,dec18-19,’06 amarjit soni het, bnl [email protected]...

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