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Experimental environment D sJ ’s and their properties X(3872)... ...and also Y(3940) cc recoil spectrum pentaquarks? Conclusion. New Resonances at Belle. B. Golob University of Ljubljana, Slovenia Belle Collaboration.

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slide1

Experimental environment

  • DsJ’s and their properties
  • X(3872)...
  • ...and also Y(3940)
  • cc recoil spectrum
  • pentaquarks?
  • Conclusion

New Resonances at Belle

B. Golob

University of Ljubljana, Slovenia

Belle Collaboration

B. Golob, Belle Cracow Epiphany Conference, 2005

slide2

Experimental environment

Mt. Tsukuba

e-

KEKB

B

Belle

Υ(4s)

~1 km in diameter

> 900 pb-1/day (~1 M BB/day)

e+

Integrated luminosity

∫Ldt = 255 fb-1 on reson.

30 fb-1 off reson.

~280 M BB

B

Oct ‘04

May ‘99

KEKB asymmetric B

factory

Υ(4s)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide3

Experimental environment

Central Drift

Chamber

e+

3.5 GeV

s(pt)/pt=

0.3% √pt2+1

3(4) layer

Si vtx det.

e-

8 GeV

combined particle ID

e(K±)~85%

e(p±→K±)<~10%

@ p<3.5 GeV/c

Aerogel

Cherenkov

Counter

(n=1.015-

1.030)

m and KL

identification

(14/15 lyrs

RPC+Fe)

1.5T SC

solenoid

EM Calorimeter

CsI (16X0)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide4

B

ECM/2

signal

ECM/2

U(4s)

e-

e+

signal

B

B

∑ pi, ∑ Ei

continuum

Experimental environment

Off reson. data:

continuum only

On reson. data:

BB (spherical) separated

from continuum

(jet shaped) on basis of

topological variables

e.g. angle

between B

direction

and beam

axis

B. Golob, Belle Cracow Epiphany Conference, 2005

slide5

DsJ states

Production in continuum

DsJ+(2460)→Ds+g

DsJ*(2317)+→Ds+p0

DsJ+(2460)→Ds*+p0

3.4

3.0

Mass (GeV)

2.6

Ds*+

2.2

Ds+

1.8

86.9 fb-1,PRL92,012002(2004)

M(DsJ(2317))=2317.2±0.5±0.9 MeV

M(DsJ(2460))=2456.5±1.3±1.3 MeV

Masses lower than

predicted

in potential models;

Widths consistent

with zero

B. Golob, Belle Cracow Epiphany Conference, 2005

slide6

DsJ states

Production in

B decays

B → DDsJ

Helicity angle:

Ds

DsJ

B

D

q

DsJ*(2317)+

→Ds+p0

g,p0

J=1

DsJ(2460)+

→Ds*+p0

DsJ(2460)+

→Ds+g

J=1

J=2

J=0

275M BB,BELLE-CONF-0461

DsJ*(2317)+→Ds+p0

DsJ(2460)+→Ds+g

Data agree with JP=0+ (DsJ(2317)) and 1+ (DsJ(2460))

Br(B0→D-DsJ*(2317)+)=(10.3±2.2±3.1)x10-4

B. Golob, Belle Cracow Epiphany Conference, 2005

slide7

First observation of B0→DsJ*-K+

DsJ states

M(Dsp0)-M(Ds)

DE

6.8 s signif.

0.2 0.3 0.4 0.5 0.6 (GeV)

-0.10 0 0.10 (GeV)

c

s

b

d

u

K+

Br(B0→DsJ*(2317)-K+)∙Br(DsJ*(2317)-→Ds-p0)

W

s

Br(B0→Ds-K+)

B0

d

152M BB,hep-ex/0409026

Br(B0→D-DsJ*(2317)+)∙Br(DsJ*(2317)+→Ds+p0)

DsJ

Br(B0→D-Ds+)

d

DsJ*(2317)-→Ds-p0

(Ds→fp,K*K,KSK)

Br(B0→DsJ(2317)-K+)∙ Br(DsJ(2317)-→Ds-p0)=

(5.3 ± 1.4± 0.7 ± 1.4)x10-5

4-quark

content?

<2.5x10-5 @90% CL

<0.94x10-5

<0.40x10-5

B→DsJ(2317)p-

B→DsJ(2460)K+

B→DsJ(2460)p-

= 1.8 ± 0.6

= 0.13 ± 0.05

B. Golob, Belle Cracow Epiphany Conference, 2005

slide8

Observed by Belle with

152M BB

B± → K± p+p-J/y

l+l-

How about with 275M BB?

152M BB,

PRL91,262001

(2003)

275M BB,S.Olsen,GHP’04

X(3872)

Calculate Mbc in 5 MeV bins ofM(p+p-J/y)

M(p+p-l+l-)-M(l+l-)

3865

MeV

48.6±7.8 evts.

(>10s)

M=3872.4

±0.7 MeV

3870

MeV

no. of

B’s in

bins of

M(p+p-J/y)

3875

MeV

M(p+p-l+l-)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide9

B± → K± p+p- p0 J/y

Mbc andDE

in 25 MeV

bins of

M(p+p-p0)

X(3872)

-0.1 0.1

5.20 5.25 5.30

Mbc

DE

M(p+p-p0J/y)= M(X)± 3s

no. of B’s in

bins ofM(p+p-p0)

13.1±4.2 evts.(6.4s)

M(p+p-p0)>750 MeV

consistent with 0

First observation of decay mode

other than p+p-J/y;

subthreshold decay to wJ/y

(expected for DD* molecule)

C(X(3872))=+1

B. Golob, Belle Cracow Epiphany Conference, 2005

slide10

Dalitz plot for

B→ KwJ/y

Y(3940)

B→ Kp+p- p0 J/y

B± → K* J/y; K*→ K± w

Events in DE, Mbc signal region

resonant

structure?

M2(J/yw)

M(p+p-p0J/y)

B→

KwJ/y

M(p+p-p0)

M2(Kw)

For these

B→ KwJ/y

plot Mbc, DE in bins

ofM(wJ/y)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide11

B± → K± wJ/y

No. of B’s

in bins of

M(wJ/y)

275M BB,

hep-ex/0408126

Y(3940)

40 MeV binsM(wJ/y)

3897

MeV

3937

MeV

3977

MeV

large

deviations

from phase

space

M(Y)=3943±11±13 MeV

G=87±22±26 MeV

58 ± 11 evts.

Fit with

added

BW

(8.1s)

Relatively large signal at

lowM(wJ/y)

Br(B→YK)Br(Y→wJ/y)=

(7.1±1.3±3.1)x10-5

B. Golob, Belle Cracow Epiphany Conference, 2005

slide12

cc recoil spectrum

X

e-

e+

J/y

hc

cc0

hc(2s)

well established method(e.g. double cc

production)

Reconstruct

J/y →l+l-

Calculate recoil mass (mass of X):

285 fb-1,T.Ziegler,GHP’04

new resonance

N=148 ± 33 (4.5 s)

M=3940 ± 11 MeV

Reconstruction of

additional D or D*

besideJ/y→

- new resonance decays

to DD*;

- not seen in J/y w

probably not Y(3940)

confirmation of hc(2s) after 1st

observation by Belle

B. Golob, Belle Cracow Epiphany Conference, 2005

slide13

Pentaquark searches

M(pK-)

y[cm]

L(1520)

M(pKS)

x[cm]

(KN+(1540)X)

(KN(1520)X)

< 2%(90%CL)

155M BB,hep-ex/0411005

Searches in decays,“high energy” (charm baryon,B)

Searches in secondary interactions,“low energy”

select pK secondary vtx

detector “tomography”:

M(pK-)fit

with D-wave

BW and

treshold

funct.;

L parameters

in agreement

with PDG

M(pKS) fit with 3rd order

poly.and narrow sig.(2 MeV)

at different m

assuming Br(+→pKS)=25%

B. Golob, Belle Cracow Epiphany Conference, 2005

slide14

Pentaquark searches

B0  p pKS

B0  p+ D(*)-p

B+  p pK+

B0 pD0p

B0  p+D-p

155M BB,hep-ex/0411005

B decays

Qc0

Q(1540)+

Qc*+

Q*(1600)++

303

±21

evts.

M(Qc0)=3099 MeV(H1)

s=3.5 MeV (det. resol.)

@90% CL

B. Golob, Belle Cracow Epiphany Conference, 2005

slide15

KEKB is also a great source of charm& cc states

  • Some expected, mainly unexpected/puzzling

observations/discoveries

D**broad states

PRD69,112002

Y(3940)

hep-ex/0408126

DsJ properties

BELLE-CONF-0461

hep-ex/0409026

hc(2s)

PRL89,102001

PRD70,071102

PQ

searches

hep-ex/0411005

X(3872)→ wJ/y

S.Olsen,GHP’04

Sc(2800)

hep-ex/0412069

resonance in cc

recoil

T.Ziegler,GHP’04

Lc+ p structure

hep-ex/0409005

Conclusions

range of questions:

understanding

all properties

as expected?

why such

properties?

what are they?

will be addressed as more statisticsis collected

B. Golob, Belle Cracow Epiphany Conference, 2005

slide18

Pentaquark searches

M(pK-)

L(1520)

M(pKS)

(KN+(1540)X)

(KN(1520)X)

< 2%

155M BB,hep-ex/0411005

backup slide

Searches in sec. inter.

select pK secondary vtx

detector “tomography”:

M(pK-)fit

with D-wave

BW and

treshold

funct.;

L parameters

in agreement

with PDG

y[cm]

Q(1540)+

M(pKS) fit with

3rd order poly.

and narrow sig.

(2 MeV) at

different m

x[cm]

@90% CL

assuming Br(+→pKS)=25%

m

B. Golob, Belle Cracow Epiphany Conference, 2005

slide19

Pentaquark searches

L(1520)

p

p

formation

p(pK-)~500 MeV

K-

K-

L(1520)

p

p

production

majority

K-

K-

assuming Br(+→pKS)=25%

Br((1520)→pK-)=

0.5 Br((1520)X→NK)

ratio of e from MC

(KN+(1540)X)

(KN(1520)X)

< 2%(90%CL)

backup slide

L(1520)

spectrum

(fit to

M(pK-) in

mom. bins

formation

p

non-zero

strangeness

most pK vtx

produced by

strange

particles

vtx with addit.

track

distance

pK- vtx –

next track

distance

pK- vtx –

next K+

cm

B. Golob, Belle Cracow Epiphany Conference, 2005

slide21

Production in B decays

DsJ states

backup slide

Decay channel Br[10-4] signif.

B  D DsJ(2317) [Dsp0] 10.1  1.5  3.0 9.5s

B  D DsJ(2317) [Ds*g] 4.0-1.4+1.5 (<8.4) 3.5s

B  D DsJ(2460) [Ds*p0] 14.8-2.5+2.8  4.4 8.6s

B  D DsJ(2460) [Dsg] 6.4  0.8  1.9 11s

B  D DsJ(2460) [Ds*g] 2.6-1.0+1.1 (<5.7) 3.0s

B  D DsJ(2460) [Dsp+p-] 1.0-0.4+0.5 (<2.3) 2.6s

B  D DsJ(2460) [Dsp0] 0.2-0.5+0.7 (<1.7) --

B  D* DsJ(2317) [Dsp0] 3.1-1.7+2.1 (<8.5) 2.0s

B  D* DsJ(2460) [Ds*p0] 28.7-6.4+7.4  8.6 6.9s

B  D* DsJ(2460) [Dsg] 12.7-2.0+2.2  3.8 10s

Br(DsJ(2460)→Ds+g)/Br(DsJ(2460)→Ds*+p0)=0.43±0.08±0.04

Br’s from DE fits in Mbc and M(DsJ) signal region

Largest syst. uncertainty from p0 eff. and D branching

fractions

B. Golob, Belle Cracow Epiphany Conference, 2005

slide23

Y(3940)

backup slide

B→ KwJ/y

DE in 40 MeV bins

ofM(wJ/y)

|DE| < 0.03 GeV, 5.2725< Mbc< 5.2875 GeV

all fits consistent yield

within stat. error (~200±20)

B yield inM(wJ/y)

bins for B→ KwJ/y

phase space MC

Yields determined from

simultaneous DE and Mbc fits

(constrained to be equal);

peak position and width from fits

to integrated distrib.

Fit with f(M)=Aq*(M)

q*(M): mom. of daughter part.

in wJ/y frame

B. Golob, Belle Cracow Epiphany Conference, 2005

slide24

Nw=74±14

Y(3940)

backup slide

B→ KwJ/y

M(p+p-p0)

DE, Mbc signal region

20% variation

included in

syst. error.

Ks,K± yields

consistent

with acc.

ratio.

acceptance

KS

M(wJ/y)

M(wJ/y)<3997 MeV

(first 3 bins in

M(wJ/y));

no resonance

in Kw in this

M(wJ/y) region

M(Kw)

DE, Mbc side band:

Nw=14±10(non-w 3p)

fraction of true w

in signal: 0.90±0.18

(in syst. error)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide25

Y(3940)

backup slide

B→ KwJ/y

Main syst. uncertainty:

fit using S-wave BW or Lorentzian shape for resonance;

linear or 3rd order polynomial for bckg.;

largest deviation +38%

possible non-w 3p contribution;

-28%

Significance:

integral of fitted phase space in first 3 bins of M(wJ/y)

16.8±1.4

total number of events: 55.6

significance > 9s

> 8s

B. Golob, Belle Cracow Epiphany Conference, 2005

slide27

Lc+ p structure

Sc(2455)0

Sc(2520)0

B-→ Lc+ p p-

D(1600)

D(2420)

152M BB,hep-ex/0409005

3-body baryon production in

B decays: baryon-antibaryon

system peaked near treshold

Fits to DE

in mass bins

264±20 evts.

Lc+ →pK-p+,pKS,Lp+,

pKSp+p-,Lp+p+p-

L→ pp-

BW peak + feed

down fromB-→ Lc+ D

M = 3.35 ± 0.02 GeV

50 ± 10 evts.(5.6 s)

G~70 MeV

B. Golob, Belle Cracow Epiphany Conference, 2005

slide28

Lc+ p

Lc+ p structure

Br(B-→ Sc(2455)0 p)=(3.67+0.74-0.66 ± 0.36 ± 0.95)∙10-5

Br(B-→ (Lc+ p)p-)=(3.87+0.77-0.72 ± 0.43 ± 1.01)∙10-5

Sc(2455)0 p

Sc(2455)0 p

simultaneous fit

to 6 DE distrib.;

Ni=SjeijYj

Lc+ D(2420)

Lc+ D(1600)

Lc+ D(1232)

due toBr( Lc+ → pK-p+ )

M=3.35 +0.01-0.02 ± 0.02 GeV

G=0.07 +0.04-0.03± 0.04 GeV

from different bkgd. param.

B. Golob, Belle Cracow Epiphany Conference, 2005

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