B. Golob, Belle Charm physics at Belle 1Belle Rev. Comm. 2007 B. Golob University of Ljubljana Belle...

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B. Golob, Belle Charm physics at Belle 1 Belle Rev. Comm. 2007

B. GolobUniversity of Ljubljana

Belle Collaboration

Outline1. Introduction

2. Spectroscopy

3. Semileptonic D decays

4. D0 - D0 Mixing

5. Summary

Charm Physics at Belle

B-factory, c-factory

Introduction

√s = M((4S))c2=10.58 GeV

(B B) 1.1 nb (~750·106 BB pairs)

(c c) 1.3 nb (~850·106 XcYc pairs)

Physics of c-hadrons increased interest at B-factories in recent years

Dual role of charm standalone field of SM tests and search for new phenomena (SM and/or NP) - measurements of known and new charmed baryons and mesons - measurements of new “exotic” states - understanding of charmonia production and decay - charm fragmentation - D0 mixing and CPV experimental tests of theor. predictions (most notably of (L)QCD); improve precision of CKM measurements (B physics); - meson decay constants and form factors - confrontation of spectroscopic results and predictions - charm branching fractions

c(2880)

c(2940)

c(2765)

1st observ.signnce > 6

New c-baryons

Spectroscopy

c → c+ K- +;

neutral states also observed, iso-doublet

Charm mesons and baryons laboratory to test predictions of quark model(s), HQS, Skyrme model, Regge trajectories, ....

PRL97, 162001 (2006) 460 fb-1

405 ± 50 evtssignificance 5.7

State Mass [MeV/c2] Width [MeV/c2]

c(2980)+ 2978.5±2.1±2.0 43.5±7.5±7.0

c(3080)+ 3076.7±0.9±0.5 6.2±1.2±0.8

confirmed by BaBar, hep-ex/0607042

hep-ex/0608043, 553 fb-1, subm. to PRL

c(2880) → c(2455) c+- with M(c±) ~ M(c(2455))

JP of c(2880) and c(2940) → c(2455) BaBar, PRL98, 012001 (2007), 287 fb-1

New c-baryons

Spectroscopy

c(2880)→ c(2455) angular distribution

c(2455)

JP=5/2+ strongly favored

hep-ex/0608043, 553 fb-1, subm. to PRL

prospects (1 ab-1)

)%5.22.65.22())2455()2880((

))2520()2880(( *

c(2880)→ c(2455/2520) → ±4.5%;- c(2940) → c(2455) yield ~450, ang. analysis JP;- c (2980)0→ c

+ KS -

sign. → ~ 3 ; confirmation in other decay modes;goal: well established ensemble of hadrons with determined quan. num., to be confronted to theory A. Selem, F. Wilczek, hep-ph/0602128

deviations from linear Regge traj.

Double cc production

Spectroscopy

PRL98, 082001 (2007) 350 fb-1

recoil method2

/ )( JJcmsrec pEEM

266±63 evts

M=3943±6±6 MeV/c2

<52 MeV @90% C.L.

c1’ (23P1), c’’ (31S0)?

prospects (1 ab-1) recoil method: “factory” of cc with C=+1;

3 sensitivity min(e+e- →J/X) ~ 5-10 fb ((J/c) = 25 fb)

Spectroscopy

“Exotic” statesno obvious predicted candidates;most prominent X(3872);DD* molecule?number of results, recently:B → (D0 D0 0)K

PRL97, 162002 (2006), 414 fb-1

24.1 ± 6.1 evts 6.4

M=(3875.2 ± 0.7 ± 0.31.6 ± 0.8) MeV/c2

confirmed by BaBar, P. Grenier, 42nd Moriond QCD (2007), 347 fb-1

PRL91, 262001 (2003) 152M BB

B → X(→D0 D0 0) Kif enhancement X(3872)

1.36.3

8.8)/(

large mixing between c1’ and X(3872)?

other measurements: JPC=1++, 2-+;J=2: supressed decay to DD*, JPC=1++?

hard to accommodate in molecularmodel (~0.08) E.S.Swanson,

Phys.Rept. 429, 243 (2006)

2.5 diff. with X → J/

Spectroscopy

“Exotic” statese+e- → Y(→J/ ) ISR

BaBar, PRL95, 142001 (2005), 233 fb-1

hep-ex/0612006, 553 fb-1

165 +25-33 evts

sign.: 11

M=(4295 ± 10 ± 103 ) MeV/c2

=(133 ± 26 ± 136 ) MeV

2.5 difference with M from BaBar

Y(4260)

D*+D*-

Exclusive (e+e- → D*D(*))

using ISR; partial recon., (Mrec)=1 MeV Mrec= Mrec(D(*)+ ISR) - Mrec(D(*)+ - ISR); data to help understand Y(4260) nature; coupled channels effects (Ds*Ds*, DD1

thresholds), hybrid state (decays to DD1, M?)

M.B. Voloshin, hep-ph/0602233 S.L. Zhu, PLB625, 212 (2005)

PRL98, 092001 (2007), 550 fb-1

in agreement with Cleo-c scans < 4.25 GeV

Spectroscopy

c(2800)

c(2980)

c(3077)

c(2880) hep-ex/0608043

PRL97, 162001

PRL94, 122002

DsJ(2715) hep-ex/0608031

X(3872)

X(3940)

Y(3940)

Z(3930)

Y(4260)

hep-ex/0505037

hep-ex/0505038

PRL91, 262001

PRL97, 162021

PRL98, 082001

PRL94, 182002

PRL96, 082003

hep-ex/0612006

prospects (1 ab-1)

X(3872): new results B →XK to test models Br(B0 →KSX)/Br(B+ →K+X) ~ ±15% molecular model: 6-29% M(Xh)-M(Xl) ~ ±1 MeV tetra-q model: 8 ±3 MeV

Y(4260): data to help interpretation combining e+e- → Y(→J/ ) ISR and (e+e- → D(*)D(*)); M ~ ±10 MeV/c2; enough to distinguish from thresholds? min ~ ±15% in each mode

e.g. F.E. Close, P.R. Page, PLB578, 119 (2004)

L. Maiani et al., PRD71, 014028 (2005)

Semileptonic D decays

D0 semileptonic decays determination of form factor; test of LQCD to ±5%;

e+e- → Dtag(*)Dsig*;

inverse reconstruction; start from Dtag

(*) and CMS momentum recoil momentum;

method enables: - good q2 resolution ((q2)~0.0145 GeV2/c2) - absolute normalization (inclusive D0 signal)

signal: p2()=0;

PRL97, 061804 (2006), 282 fb-1

|Vub| from B0 → l : ±14% from f.f., ±3% from Br

D0 → N=106±12

D0 → e N=126±12

m2 [GeV2]

fake-D0 bkgdata

hadronic bkgdata

Kl bkgdata

l bkgMC

current lumin.

expected accuracy

D0 → K l

D0 → l

Semileptonic D decays

D0 semileptonic decays competitive (K) l Br measurement;

PRL97, 061804 (2006), 282 fb-1

Y. Gao (Cleo-c), ICHEP06, 281 pb-1

first direct Br(D0 → ) determination;

comparison to LQCD;

f+D(0) = 0.624 ± 0.020 ± 0.030

unquenched: C. Aubin et al., PRL94, 011601 (2005)f+

D(0) = 0.64 ± 0.03 ± 0.05

D0 - D0 Mixing

Mixing phenomena

well known in K0, Bd0 and Bs

0 system (last year); eluded observation so far in the D0 system;

d, s, b d, s, b

002,1 DqDpD

; 2121 ymm

d-like quarks exchanged;effective GIM suppression;

D0 decays: CF; mixing: DCS;x, y ~ sin2C (SU(3) breaking)

difficult to calculate;x, y affect the t distribution of D0, observables;largest predictions in SM: |x|, |y| 10-2

I.I. Bigi, N. Uraltsev, Nucl. Phys. B592, 92 (2001);A.F. Falk et al., PRD69, 114021 (2004)

CPV in D0 system:first two generations involved;Wolfenstein param., (Vcs)=A24 ~ O(10-3)

D0 - D0 Mixing

D0 → KS +- t-dependent Dalitz analysis different decays (CF, DCS, CP eigenstates) identified through Dalitz analysis; their relative phases determined;

titititi eemmp

tDftmm

2121 ),(2

)(),,(

MMAA ,1p

arXiv: 0704.1000

no CPV

< f | D0 > < f | D0 > 1,2=f(x,y);

analogous for M = < f | D0(t) >

fit M(m-2,m+

2,t) to data distribution x, y

Two recent Belle measurements - decays to CP final state, D0 → K+K-/+-

- decays to hadronic multi-body final state, D0 → KS +-

common:D*+ →D0s

p*(D*) > 2.5 GeV/c

D0 - D0 Mixing

D0 → KS +-

arXiv: 0704.1000

signal in M(KS +- ) and

Q= M(KS +-s)- M(KS +-)- M()

M Q signalrnd slow combin.

(534.4±0.8)x103 evts

Dalitz model: 13 BW resonances, non-resonant contr.;

test of S-wave contr.: K-matrix formalism

K*(892)- K*(892)+

K*X(1400)+

Results (fit fractions, phases) in agreement with (measurement of 3)

PRD73, 112009 (2006)

D0 - D0 Mixing

D0 → KS +-

arXiv: 0704.1000

t [fs]

x = 0.80±0.29±0.17 %y = 0.33±0.24±0.15 %

= 409.9±0.9 fs

most sensitive meas. of x;

Cleo, PRD72, 012001 (2005)x = 1.8 ± 3.4 ± 0.6%y = -1.4 ± 2.5 ± 0.9 %

PDG=410.1±1.5 fs

t-projection

D0 - D0 Mixing

D0 → K+K- / +-

hep-ex/0703036v2

CP even final state;t distribution not pure exponential (D1 and D2 contr.);

treated as exponential changed effective

S. Bergman et al., PLB486, 418 (2000)

AM, : CPV in mixing and interference;

CPV: D0 → f and D0 → f decay rates different; effective different

sideband

K+K- K-+ +-

Nsig 111x103 1.22x106 49x103

P 98% 99% 92%

sincos2

)()(00

KKDKKD

KKDKKDA

M, Q, t selection optimized in MC

D0 - D0 Mixing

D0 → K+K- / +-

hep-ex/0703036v2

simultaneous binned likelihood fit to K+K- /K-+/+- decay-t

)(')'(/' tBdttteN

dN t R

R : ideally each i Gaussian resol. term with fraction fi;pulls: described by 3 Gaussians

i kikki tsttGwftt

10 ),,'()'( R

2/ndf=1.084 (ndf=289)

= 408.7±0.6 fs

D0 - D0 Mixing

D0 → K+K- / +-

hep-ex/0703036v2

results yCP = (1.31 ± 0.32 ± 0.25) %

evidence for D0 mixing(regardless of possible CPV)

3.2 from zero (4.1 stat. only)

K+K-/+-

and K-+ratio

search for CPV:

A = (0.01 ± 0.30 ± 0.15) %difference of lifetimesvisually observable

KS +- : (x,y)=(0,0) has C.L. 2.6%

K+K- / +-: y=0 has C.L. 6x10-4

D0 - D0 Mixing

perspective (1 ab-1)1

x, y at upper limit of SM expectation search for CPV; at current level of sensitivity positive signal clear indication of NP;

preliminary study in KS+-: (|q/p| 1 + AM/2) ~ 0.30, () ~ 17o

K+K- / +-: (A/yCP AM/2 - x/y tan) ~ 0.25

combination at 1 ab-1:

(x) ~ ±0.21%(y) ~ ±0.17%

() ~ 9o, (|q/p|) ~ 0.15

Summary

Belle great exp. environment for charm studies; complementary to c-factories;

In several areas exp. results ahead of theor. predictions in accuracy

Spectroscopic results: conventional states - confrontation with predictions; “exotic” states - new challenge; all - quantum number determ.

(Semi)leptonic D meson decays: tests of non-pert. QCD

First evidence for D0 mixing: more precise determ. of parameters and search for CPV

Spectroscopy, c, bckup

c → c+ K- +;

no reflections in c+ K+ -

Wrong sign charge comb.: c+ K+ -;

possible reflections from c*+ → c

+ + - with misidentified as K would appear here

PRL97, 162001 (2006) 460 fb-1

neutral states also observed, iso-doublet

State Mass [MeV/c2] Width [MeV/c2]

c(2980)+ 2978.5±2.1±2.0 43.5±7.5±7.0

c(3080)+ 3076.7±0.9±0.5 6.2±1.2±0.8

c(3080)0 3082.8±1.8±1.5 5.2±3.1±1.8

c → c+ K- +;

BaBar: 2-D fits in M(cK) and M(c)

hep-ex/0607042

cKnon-res.

c → c+ K- +;

new states; Belle discoveries and measurem.

J.L. Rosner, hep-ph/0609195

high mass L=2?

Sl = 0 (lightestorbital excit.)JP = 5/2+, 3/2+

5/2+ → c F-wave3/2+ → c P-wave

Spectroscopy, c, bckupBelle, hep-ex/0608043, 553 fb-1, subm. to PRL

c(2455)

2/ndf = 49.9/9 (J=1/2) 36.0/8 (J=3/2) 10.8/7 (J=5/2)

angular analysis

repeat fit in bins of

J=5/2 strongly favored

c(2880) JP

c(2880)→c(2455)

c(2880)→c(2520)

c(2880)→c

c(2880) JP

repeat fit in bins of M(c±) c(2880)) vs M(c±)

c(2880) P interpretation

HQS: 5/2+ sl l 2+ 3+

c*/c 0.24 0.37

5/2- sl l 2- 3-

c*/c 1.46 0.12M(2880)=2881.2±0.2±0.4 MeV

N. Isgur, M.B. Wise, PRL66, 1130 (1991)

S. Capstick, N.Isgur, PRD34, 2809 (1986)

comparison of two charged states;

reflections from c(2980, 3077) → c

+K-+ with K- misid.

appear in c++ -

but not in c0 +

c(2880) JP

Spectroscopy, 2cc, bckup

Double cc production(e+e-→J/X)(fb) exp. LO NLOc 25.6±2.8±3.4 3.78±1.26 18.9

c0 6.4±1.7±1.0 2.40±1.02

c(2S) 16.5±3.0±2.4 1.57±0.52

Belle, PRD70, 071102 (2004)

E. Braaten, J. Lee, PRD67,054007 (2003)

Y. Zhang et al., PRL96 ,092001 (2006)

PRL98, 082001 (2007) 350 fb-1

C() = -1

C(J) = -1C(X) = +1

C() = -1

C(X) = -1

X(3940)→D(*)D ?reconstruct J/ + one DMrec(J/D) ~ M(D(*))

constrain Mrec(J/D)=M(D(*))(Mrec(J/))~10 MeV/c2

Mrec(J/D)=M(D)

Mrec(J/D)=M(D*)24.5±6.9evts5

no evidence forX(3940)→J/ X(3940)≠Y(3940)

inclusive/D*D tagged sample,common evts removed

B>2(X→D*D) > 45% @90% C.L.B(X→D D) < 41% @90% C.L.B(X→J/) < 26% @90% C.L.

PRL98, 082001 (2007) 350 fb-1

X(3940)=c1’?

DD* mode dominantno c1 in Mrec,

X(3940)=c’’?

expected mass 4040-4060 MeV/c2

PRL98, 082001 (2007) 350 fb-1

Spectroscopy, DsJ, bckup

B+ → D0D0K+

hep-ex/0608031 414 fb-1

fit to E, Mbc

in bins of M(D0K)

Spectroscopy, X, bckup

Possible JPC

C parity B±,0 → K±,0 X (→ J/) 13.6 ± 4.4 evts.(4)

mode with substantial Br

B±,0 → K±,0 c1 (→ J/)serves for calibration of width

hep-ex/0505037, 275M BB

C(X(3872))=C()·C(J/)=+1

05.014.0)/(

JXBrconfirmed by BaBar, PRD74, 071101 (2006), 260 fb-1

0-+, 1--, 1+-, 0++, 1++, 2++, 2-+, 2--, 3--

Angular distributions

B±,0 → K±,0 X (→ +- J/)(only examples shown)

X(J/)+

|cos()|

2/ndf=31/9 JPC=0++

JPC=1++

|cos()|

2/ndf=5/9

in the limit where X, J/rest frames coincidedN/d(cos()) sin2()

relative motion of frames included in MC

cc JPC

hep-ex/0505038, 275M BB

B → (D0 D*0)K BaBar: D*0 → D0 0 / D0

BaBar, P. Grenier, 42nd Moriond QCD (2007), 347 fb-1

Spectroscopy, Y, bckup

Coupled channels

threshold DD1, 4285 MeV/c2

M(Y)=4295 MeV/c2

parameterization acc. to

Y(4260)

M(D)+M(D1) E [GeV]

(e+e- → D*D*)

4265 GeVM.B. Voloshin, hep-ph/0602233

hep-ex/0607083

Exclusive (e+e- → DD) BaBar

Semileptonic D decays, bckup

D0 semileptonic decays determination of form factor, test of LQCD;

e+e- → Dtag(*)Dsig*;

inverse reconstruction: Dtag

(*) fully reconst. K n, n=1,2,3; p(Dtag), p(e+e-), p(primary , K) p(Dsig*); +

slow from Dsig*+ →D0 +slow

p(D0sig);

and l p();

PRL97, 061804 (2006), 282 fb-1

tag signal

primary mesons

D0 → K eD0 → K N=1318±37N=1249±37

K l signal

m2 [GeV2]

D0 semileptonic decays determination of form factor, test of LQCD;

PRL97, 061804 (2006), 282 fb-1

D0 → e

Y. Gao (Cleo-c), ICHEP06, 281 pb-1

f+D(0) = 0.624 ± 0.020 ± 0.030

f+D(0) = 0.670 ± 0.028 ± 0.011 ± 0.009

Br results:

D0 semileptonic decays background

fake D0: from WS sample (Dtag, Dsig same flavor);

Kl (in l ): from measured Kl with independently measured fake rate;

hadronic (misid as l): sample with charge of l opposite to the s from D*sig (OS sample); contains no signal and no semil. background;

use K and intentionally misid-ed as l; fit the OS sample amount of and K misid-ed background

PRL97, 061804 (2006), 282 fb-1

D0 - D0 Mixing, KS+-, bckup

D0 → KS+-

Dalitz results

arXiv: 0704.1000

D0 → KS+-

systematics

arXiv: 0704.1000

D0 → KS+-

systematics

arXiv: 0704.1000

Systematics (largest) model dependence [10-4]: x y +12.5 +5.0 variation of DCS/CF - 6.4 -4.4 ratios for K*'s

±7.3 ±5.8 K-matrix --------------------------------- +14.6 +7.8 Total model dep. -13.5 -8.5

t fit: x y +7.6 -7.8 p* variation -5.6 -5.7 Dalitz pdf for bkg. from different t bins ----------------------- +8.6 +7.9 Total t fit -6.7 -11.6

Total [10-4]: x y +17 +11 -16 -15

D0 → KS+-

scalar

arXiv: 0704.1000

BW formalism:M(1) = 527 ±6 MeV/c2

(1) = 442 ± 10 MeV

M(2) = 1031 ±11 MeV/c2

(2) = 94 ± 6 MeV

qkpqjpjkjk TiTTT 2

K-matrix formalism:unit. relat. for 2-body scatt. trans. operator:

T: NchxNch matrixfor Nch coupled chann.;: density of final states

product. process (init. state non-interactingwith channel j); trans. ampl. unitarity:

qjpqpjj TiFFF ** 2

qjqj TaF1

satisf. by

defining 1)( KiIKT

unitarity satisf. if KK

product. ampl.:1)( KiIaKF

4:3:2:1

aKKiIFj

V.V. Anisovich, A.V. Sarantev, Eur.Phys.J. A16, 229 (2003)BaBar, hep-ex/0507101

parameters taken from:

D0 → KS+-

efficiency and resol. in M(

arXiv: 0704.1000

Prnd [(1-fw) M(m-2,m+

2,t) +fw M(m+2,m-

2,t)] R(t)

fw from fit to Q side band: fw= 0.452 ± 0.005

diff. w.r.t. fw=0.5 in systematic error

D0 → KS+-

arXiv: 0704.1000

MC tests, correct reconstruction of input;

t-projection;

Psig M(m-2,m+

2,t) R(t)

Prnd [(1-fw) M(m-2,m+

2,t) +fw M(m+2,m-

Pcmb [ (t) + Exp(t) ]R’(t)

D0 - D0 Mixing, K+K- / +-, bckup

M [GeV/c2]

D0 → K+K- / +-

hep-ex/0703036v2

D0 → K+K- / +-

systematics

hep-ex/0703036v2

D0 → K+K- / +-

running periods w/ diff. conditions

fitted t0 of R for K

robust to resol. f. shape; R(t): single Gauss →=3.5%, yCP=0.01%;

no bias, reweigted MC: yCP(out) - yCP(in) < 0.04%;

background P=98% (KK), 99% (K), 92% (); changing data side band/MC signal, yCP = -0.04%; bkg. subtracted / no bkg. subtraction, yCP = -0.07%; bkg. subtracted / MC signal subtr., yCP= -0.03%;

systematic checks

hep-ex/0703036v2

D0 → K+K- / +-

fitted t0 of R in diff. run periods and diff. decay modes

hep-ex/0703036v2

D0 → K+K- / +-

equal t0 assumption

yCP=t0CP - t0

from MC cocktail, includingrunning periodswith slight misalign.of SVD

hep-ex/0703036v2

D0 → K+K- / +-

background comparison

small tail ofsignal present inside band, only visible in K sample;

fraction of rnd s

negligible:0.3%, 0.3%, 0.2%KK K

hep-ex/0703036v2

D0 - D0 Mixing, prosp., bckup

Combination numbers very preliminary

(yCP) ~ 0.15%, (A/yCP) ~ 0.10

(x) ~ (y) ~ 0.15%, (|q/p|) ~ () ~ 0.10

(x’2) ~ 0.12x10-3, (y’) ~ 0.20%

(x) ~ (y) ~ 0.10%(cos ) ~ 0.07(|q/p|) ~ 0.09, () ~0.05 rad

D0 → K+K- / +-

D0 → KS+-

D0 → K+-

combined

approximate projections to 5 ab-1

B. Golob, Belle Charm physics at Belle 1Belle Rev. Comm. 2007 B. Golob University of Ljubljana Belle...

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