Inclusive four charm hadron production at Belle

Inclusive four charm Inclusive four charm hadron production hadron production

at Belleat Belle

June 16-20, 2005June 16-20, 2005International Conference on QCD International Conference on QCD

and Hadronic Physics, Beijingand Hadronic Physics, Beijing

JUNGIL LEEJUNGIL LEE

2JUNGIL LEE, Korea University

OutlineOutline Brief Review on NRQCD and Brief Review on NRQCD and

quarkonium physicsquarkonium physics Belle measurement of Belle measurement of [e[e++ee-- J/ J/ cc]] Previous trials to resolve the large Previous trials to resolve the large

discrepancy between theory and datadiscrepancy between theory and data A test by using four charm hadron A test by using four charm hadron

final statefinal state DiscussionDiscussion

Brief Review Brief Review on NRQCDon NRQCD


NRQCD is an Effective Field NRQCD is an Effective Field Theory of QCD Theory of QCD

that describes Heavy that describes Heavy QuarkoniumQuarkonium

NRQCD[Bodwin,Braaten,Lepage,PRD(‘95)] NRQCD[Bodwin,Braaten,Lepage,PRD(‘95)] describes Quarkonium from first principles.describes Quarkonium from first principles.

NRQCD solved the problem of Infra-Red NRQCD solved the problem of Infra-Red Divergencies in the Color-Singlet ModelDivergencies in the Color-Singlet Model

[Bodwin,Braaten,Lepage,PRD(‘92)][Bodwin,Braaten,Lepage,PRD(‘92)]


Experimental Verification of Experimental Verification of NRQCD FactorizationNRQCD Factorization

Following the theoretical success that Following the theoretical success that solved the Infra-Red Divergence problem, solved the Infra-Red Divergence problem,

theorists applied NRQCD to issues on theorists applied NRQCD to issues on quarkonium decays and productions.quarkonium decays and productions.

The first experimental success of NRQCD The first experimental success of NRQCD in quarkonium production was in quarkonium production was

at the Fermilab Tevatron.at the Fermilab Tevatron.


Tevatron Anomaly, resolved by Tevatron Anomaly, resolved by NRQCDNRQCD

As an effective field theory of QCD, As an effective field theory of QCD, NRQCD replaced a 20-year-old NRQCD replaced a 20-year-old phenomenological model at the Fermilab phenomenological model at the Fermilab Tevatron. Braaten,Fleming(’95)Tevatron. Braaten,Fleming(’95)


J/J/ Polarization confronts Polarization confronts NRQCD?NRQCD?

According to NRQCD, J/According to NRQCD, J/ produced at large produced at large ppTT must be transversely polarized. However, must be transversely polarized. However,CDF measurement seems to contradict the CDF measurement seems to contradict the prediction. People have been curious about prediction. People have been curious about the reason. the reason.


Lattice NRQCD calculation ofLattice NRQCD calculation ofPolarized matrix elementsPolarized matrix elements

Lattice NRQCD calculation to estimate the Lattice NRQCD calculation to estimate the spin-flip interaction by directly spin-flip interaction by directly calculating calculating non-perturbative matrix elements from non-perturbative matrix elements from first principles. first principles.

Bodwin, Lee, Sinclair, Bodwin, Lee, Sinclair, hep-lat/0503032hep-lat/0503032 Geoff Bodwin, Plenary TalkGeoff Bodwin, Plenary Talk June 20, 3:50PMJune 20, 3:50PM

IT’S experimentalists’ IT’S experimentalists’ ((CDF/D0) CDF/D0) TURN!TURN! Hopefully with large statistics by a Hopefully with large statistics by a factor 20.factor 20.


Chiral perturbation theory andChiral perturbation theory and

QuarkoniumQuarkonium PolarizationPolarization

In Upsilon(3S) In Upsilon(3S) Upsilon(1S), final Upsilon(1S), final quarkoniumquarkoniumPolarization is not described by QCD Polarization is not described by QCD multipole expansion, but by chiral multipole expansion, but by chiral perturbation theory.perturbation theory.We apply the same idea to gluon We apply the same idea to gluon fragmenationfragmenationinto spin-triplet quarkonium states.into spin-triplet quarkonium states.

P. Ko, J. Lee, T. Kim, P. Ko, J. Lee, T. Kim,

Pyungwon Ko, Parallel session Pyungwon Ko, Parallel session (Hall B)(Hall B) June 17, 2:30PMJune 17, 2:30PM

Belle J/Belle J/cc AnomalyAnomaly


B factories at KEK-B & SLACB factories at KEK-B & SLAC

* Collider : e* Collider : e++ee-- E EC.M.C.M.=10.6GeV[=10.6GeV[(4S)](4S)]* Detectors: KEK-B Belle, SLAC BaBar* Detectors: KEK-B Belle, SLAC BaBar

CP violation in CP violation in BBJ/J/KKss

Main GoalMain Goal

* Measured* MeasuredJ/J/cc ): ): Large discrepancy between theory & dataLarge discrepancy between theory & data

* Discoveries: * Discoveries: cc(2S), X(3872)[J/(2S), X(3872)[J/++--

Remarkable QCD Results from Remarkable QCD Results from BelleBelle


Exclusive eExclusive e++ee-- J/ J/ cc

Precision measurement Precision measurement

R=R=//~ 10~ 10-7 -7 << R<< Rhadronhadron ~ 3.6 ~ 3.6

High-luminosity B factories High-luminosity B factories Theory is clear Theory is clear Exclusive Exclusive Color-singlet Only Color-singlet Only Long-distance factors are well Long-distance factors are well

determined throughdetermined through

J/J/ e e++ee--, , cc


Belle Puzzle, Crisis of pQCD???Belle Puzzle, Crisis of pQCD???

Braaten, Lee, PRD 67 Braaten, Lee, PRD 67 (2003)(2003)

Liu, He, Chao, PLB 557 Liu, He, Chao, PLB 557 (2003)(2003)


Suggestions & a new Belle Suggestions & a new Belle analysisanalysis

Signals may Signals may include include J/J/ J/ J/

exp.exp.~110MeV~110MeV

MMJ/J/ -M -Mcc ~120MeV ~120MeV

People thought People thought thatthat

J/J/ J/ J/ is is forbiddenforbidden

BUT …BUT …


New Belle AnalysisNew Belle Analysis

Did NOT see J/Did NOT see J/ J/ J/ Upper limit compatible with Upper limit compatible with

theorytheory Puzzle: Puzzle: [J/[J/ cc] ~ ] ~ [J/[J/ J/ J/].].

Why are ONLY J/Why are ONLY J/ c c events seen?events seen? Failure of pQCD factorization?Failure of pQCD factorization? New Production Mechanism?New Production Mechanism? Or NEW PARTICLES?Or NEW PARTICLES?


ee++ee-- J/ J/ G GJ J possibility?possibility? Glue-rich process Glue-rich process (Q(Q22))J/J/gggg Safe factorization QSafe factorization Q2 2 >> M>> MGG

B-factory can probe wider mass rangeB-factory can probe wider mass range pQCD factorization[pQCD factorization[Brodsky,LepageBrodsky,Lepage] for ] for GGJJ NRQCD factorization for J/NRQCD factorization for J/ Same order in Same order in s s as as (Q(Q22))J/J/cc


A scenarioA scenario

Brodsky,Goldhaber,Brodsky,Goldhaber,LeeLee

PRL91(2003)PRL91(2003)

Signals may include Signals may include J/J/+ Glueball.+ Glueball.

Belle angular Belle angular distribution is distribution is

compatible with compatible with Spin-2 glueball.Spin-2 glueball.

Still to be studiedStill to be studied

What aboutWhat aboutFour D Four D

mesons ? mesons ?


Why 4 D final state?Why 4 D final state?

Similar parton-level processSimilar parton-level process check if perturbative corrections are largecheck if perturbative corrections are large Quark hadron dualityQuark hadron duality

Inclusive four-charm-hadron productionInclusive four-charm-hadron production


Perturbative CalculationPerturbative Calculation


DD final state studyDD final state study

Experimentally, inclusive production of 2 Experimentally, inclusive production of 2 charmed hadrons can be measured with a large charmed hadrons can be measured with a large number of events.number of events.

By comparing the measured value with the LO By comparing the measured value with the LO QCD prediction, we can estimate if the NLO QCD prediction, we can estimate if the NLO correctioncorrectionis large enough to explain the puzzle.is large enough to explain the puzzle.


Relative rate into charm Relative rate into charm mesonsmesons

DD++DD++ : D : D++DD00 : D : D0 0 DD00 =1 : 6 : 9 =1 : 6 : 9

DD++ : D : D00 : D : D++* : D* : D00* = 1 : 1 : 3 : 3 * = 1 : 1 : 3 : 3

DD++ DD00

11 11 X 1X 1

DD++* * →→ 0.30.3 0.70.7 X 3X 3

DD00* * →→ 00 11 X 3X 3

22 66

Spin singlet : Spin triplet = 1 : 3Spin singlet : Spin triplet = 1 : 3

Branching fractions spin-triplet Branching fractions spin-triplet statesstates

Relative rate into 2 charm Relative rate into 2 charm mesonsmesons


Predicted 4 charm-hadron Predicted 4 charm-hadron enventsenvents

Events(DD)=X-Events(DD)=X-section(DD)*Br*Eff*Luminositysection(DD)*Br*Eff*Luminosity

Br(DBr(D++ K K-- ++++)=9.2%)=9.2%

Br(DBr(D00 K K--++)=3.8%)=3.8%

Efficiency per hadron = 0.8Efficiency per hadron = 0.8

Luminosity = 300 fbLuminosity = 300 fb-1-1

Xsection(fXsection(fb)b)

BrBr EffEff L(fbL(fb--

11))EventEvent

ss

DD++DD++ 1/16*1/16* 0.0920.09222 0.80.866 300300 1010

DD++DD00 6/16*6/16* 0.038*0.090.038*0.0922

0.80.855 300300 1313

DD00DD00 9/16*9/16* 0.0380.03822 0.80.844 300300 44Total EventsTotal Events ≈ 3 0 Belle Analysis is Under ≈ 3 0 Belle Analysis is Under wayway


DiscussionDiscussion Belle results of exclusive two-Belle results of exclusive two-

charmonium production is a serious charmonium production is a serious challenge to perturabtive QCD as well challenge to perturabtive QCD as well as to NRQCD factorization framework.as to NRQCD factorization framework.

BaBar must confirm the Belle results.BaBar must confirm the Belle results. Failure of pQCD factorization?Failure of pQCD factorization? New Particles? New physics?New Particles? New physics? Study of the 4 charm hadrons final Study of the 4 charm hadrons final

state will provide an independent state will provide an independent constraint.constraint.

Belle analysis of the 4 charm eventsBelle analysis of the 4 charm events is under way.is under way.


Large nonperturbative Large nonperturbative effect?effect?

Ma and Si, PRD 70 (2005).Ma and Si, PRD 70 (2005). Bonder and Chernyak, PLB 612 Bonder and Chernyak, PLB 612

(2005).(2005). Braguta, Likhoded, and Luchinsky,Braguta, Likhoded, and Luchinsky,

hep-ph/0506009.hep-ph/0506009.

Non-zero kNon-zero kTT of the quark inside the of the quark inside the meson may increase the cross meson may increase the cross section.section.


NLO Corrections NLO Corrections are Now Available ! ! !are Now Available ! ! !

Zhang, Gao, and Chao, Zhang, Gao, and Chao, hep-ph/0506076.hep-ph/0506076.

NLO correction term is as large as NLO correction term is as large as 80% of LO term.80% of LO term.

A large discrepancy between theory and A large discrepancy between theory and data still exists.data still exists.

Is the perturbation series convergent?Is the perturbation series convergent?

Documents

Inclusive four charm hadron production at Belle