The hidden charm of hadrons
Download
1 / 48

The hidden charm of hadrons - PowerPoint PPT Presentation


  • 49 Views
  • Uploaded on

The hidden charm of hadrons. Stephen L. Olsen University of Hawai’i. Representing Belle. Invited talk at the Tampa APS/DPF meeting, April 19, 2005. test of QCD: “running” a s. Probe QCD from other directions. non-qq or non-qqq hadron spectroscopies: Pentaquarks: e.g. an S=+1 baryon

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' The hidden charm of hadrons' - oriole


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
The hidden charm of hadrons
The hidden charm of hadrons

Stephen L. Olsen University of Hawai’i

Representing Belle

Invited talk at the Tampa APS/DPF meeting, April 19, 2005



Probe qcd from other directions
Probe QCD from other directions

non-qq or non-qqq hadron spectroscopies:

Pentaquarks:

e.g. an S=+1 baryon

Glueballs:

gluon-gluon color singlet states

Multi-quark mesons:

qq-gluon hybrid mesons

d

u

u

d

s

u

c

u

c

c

c


This talk search for non standard mesons with hidden charm
This talk: search for non-standard mesons with “hidden charm”

u

c

u

  • standard cc mesons are:

    • best understood theoretically

    • narrow & non overlapping

  • c + c systems are commonly produced in B meson decays.

c

(i.e containing c & c)

c

c

c

c

Vcb

b

W-

cosqC

s

CKM favored


Thanks to kekb belle has lots of b mesons 1m bb pairs day
Thanks to KEKB, Belle has lots of B mesons(>1M BB pairs/day)

>1fb -1/day

Design: 10 34


Is the x 3872 non standard
Is the X(3872) non-standard?

BK p+p-J/y

y’p+p-J/y

X(3872)p+p-J/y

M(ppJ/y) –M(J/y)


Its existence is well established seen in 4 experiments
Its existence is well establishedseen in 4 experiments

CDF

9.4s

11.6s

X(3872)

D0

X(3872)

hep-ex/0406022


Is it a cc meson
Is it a cc meson?

Could it be

one of these?

3872 MeV

These states

are already

identified


No obvious cc assignment
no obvious cc assignment

hc”

hc’

cc1’

y2

hc2

y3

M too low and G too small

angular dist’n rules out 1+-

3872

G(gJ/y) way too small

G(gcc1) too small;M(p+p-) wrong

pp hc should dominate

G( gcc2 & DD) too small

SLO hep-ex/0407033


Go back to square 1
go back to square 1

Determine

JPC

quantum numbers

of the X(3872)

with minimal assumptions


J pc possibilities for j 2
JPC possibilities (for J ≤ 2)


J pc possibilities 0 ruled out j p 0 1 2 unlikely
JPC possibilities0-- ruled out; JP=0+,1- & 2+ unlikely


Areas of investigation
Areas of investigation

  • Search for radiative decays

  • Angular correlations in XppJ/y decays

  • Fits to the M(pp) distribution

  • Search for X(3872)D0D0p0



Kinematic variables
Kinematic variables

BK gJ/y

Ecm/2

e+

e-

B B

ϒ(4S)

Ecm/2

DE

CM energy difference:

BK gJ/y

Beam-constrained mass:

Mbc


Select b k g j y
Select BKg J/y

BKcc1; cc1g J/y

X(3872)?

M(gJ/y)

Mbc

Mbc

13.6 ± 4.4 X(3872)gJ/y

evts (>4s significance)

Bf(XgJ/y)

Bf(XppJ/y)

=0.14 ± 0.05


Evidence for x 3872 p p p 0 j y reported last summer hep ex 0408116
Evidence for X(3872)p+p-p0 J/y(reported last summer hep-ex/0408116)

A virtual w(782)?

12.4 ± 4.2 evts

B-meson yields vs M(p+p-p0)

Br(X3pJ/y)

Br(X2pJ/y)

Large (near max)

Isospin violation!!

= 1.0 ± 0.5


C 1 is established
C=+1 is established

  • Xg J/y only allowed for C=+1

  • same for X”w”J/y (reported earlier)

  • M(pp) for Xp+p-J/y looks like a r

CDF


J pc possibilities c 1 ruled out
JPC possibilities (C=-1 ruled out)


Angular correlations
Angular Correlations

r

Jz=0

J=0

X3872

J=0

K

z

Rosner (PRD 70 094023)

Bugg (PRD 71 016006)

Suzuki, Pakvasa (PLB 579 67)

J/y


Use 253 fb 1 275m bb prs exploit the excellent s n
Use 253 fb-1  ~275M BB prsexploit the excellent S/N

X(3872)p+p-J/y

y’p+p-J/y

Signal

(47 ev)

Sidebands

(114/10 = 11.4 ev)


0++

In the limit where

X(3872), pp, & J/y

rest frames coincide:

dG/dcosqlp sin2qlp

qlp

c2/dof = 34/9

|cosqlp|

rule out 0++


0-+

c2/dof=18/9

0-+ : sin2q sin2y

q

|cosq|

c2/dof=34/9

y

|cosy|

safe to rule out 0-+


1++

compute angles in

X(3872) restframe

1++: sin2ql sin2c

c2/dof = 11/9

ql

K

|cosql|

c2/dof = 5/9

c

|cosc|

1++ looks okay!


J pc possibilities 0 0 ruled out
JPC possibilities (0-+ & 0++ ruled out)


Fits to the m pp distribution
Fits to the M(pp)Distribution

J/y

XrJ/y has a

q*(2l+1) centrifugal barrier

q*

X

q*

r


M pp can distinguish r j y s p waves
M(pp) can distinguish r-J/y S- & P-waves

P-wave: c2/dof = 71/39

S-wave: c2/dof = 43/39

(CL=0.1%)

(CL= 28%)

q*

roll-off

q*3

roll-off

Shape of M(pp) distribution near

the kinematic limit favors S-wave


Possible j pc values j ruled out
Possible JPC values (J-+ ruled out)



Select b k d 0 d 0 p 0 events
Select BKD0D0p0 events

D*0D0p0?

M(D0D0p0)

11.3±3.6 sig.evts (5.6s)

Bf(BKX)Bf(XDDp)=2.2±0.7±0.4x10-4

Preliminary

|DE|

|DE|


X 3872 dd p rules out 2
X(3872)DDp rules out 2++

  • 1++ : DD* in an S-wave  q*

  • 2++ : DDp in a D-wave  q*5

Strong threshold suppression


Possible j pc values 2 ruled out
Possible JPC values (2++ ruled out)

1++

1++


Can it be a 1 cc state
can it be a 1++ cc state?

1++ cc1’

  • Mass is ~100 MeV off

  • cc1’  r J/y not allowed by isospin.

    Expect:

    Bf(cc1’ppJ/y)<0.1%

    BaBar measurement:

    Bf(XppJ/y)>4%

3872

-G(cc1’gJ/y) / G(cc1’ppJ/y)

Expect: ~ 40

cc1’ component of

X(3872) is ≤few %

  • G(X3872gJ/y) / G(X3872ppJ/y)

  • Measure: 0.14 ± 0.05


Intriguing fact

Intriguing fact

lowest mass

charmed meson

MX3872 =3872 ± 0.6 ± 0.5 MeV

mD0 + m D0* = 3871.2 ± 1.0 MeV

lowest mass spin=1

charmed meson

X(3872) is very near DD* threshold.

is it somehow related to that?


D 0 d 0 bound state deuson
D0D*0 bound state (deuson)?

N. Tornqvist

hep-ph/0308277

deuteron:

deuson:

attractive nuclear force

attractive force??

c

c

p

n

D

p

D*

p

u

u

2 loosely bound qqq color singlets with Md = mp+mn- e

2 loosely bound

qq color singlets with

M= mD + mD* - d


X 3872 d 0 d 0 bound state
X(3872) = D0D*0 bound state?

  • JPC = 1++ is favored

  • M ≈ mD0 + mD0*

  • Maximal isospin violation is natural (& was predicted):

    |I=1; Iz= 0> =1/2(|D+D*->+ |D0D*0>)

    |I=0; Iz= 0> =1/2(|D+D*-> - |D0D*0>)

     |D0D*0> = 1/2(|10> - |00>)

  • G(XgJ/y) < G(XppJ/y) was predicted

Tornqvist PLB 590, 209 (2004)

Equal mixture of I=1 & I =0

Swanson PLB 588, 189 (2004)

Swanson PLB 598, 197 (2004)


X 3872 conclusion
X(3872) conclusion

  • JPC = 1++

  • cc content is small

  • matches all(?) expectations for a D0D*0 bound state

C

C

u

c

u

c

a non-qq meson


Are there others is the x 3872 a one of a kind curiousity or the 1 st entry in a new spectroscopy
Are there others?Is the X(3872) a one-of-a-kind curiousity? or the 1st entry in a new spectroscopy?

Look at other B decays  hadrons+J/y:

BK h J/y

BK p J/y

BK w J/y


B k w j y in belle
BK wJ/y in Belle

“Y(3940)”

M≈3940 ± 11 MeV

G≈ 92 ± 24 MeV

Mbc

Mbc

Mbc

S.K. Choi et al hep-ex/0408126

to appear in PRL


Y 3940 what is it
Y(3940): What is it?

Brambilla et al (QWG) hep-ph/0412158

  • Charmonium?

    • Conventional wisdom: wJ/y should not be a discovery mode for a cc state with mass above DD & DD* threshold!

  • Some kind of w-J/y threshold interaction?

    • the J/y is not surrounded by brown muck; can it act like an ordinary hadron?

w

J/y


Y 3940 what is it cont d
Y(3940): What is it (cont’d)?

  • another tetraquark?

    • M ≈ 2mDs

    • not seen in YhJ/y

      • (h contains ss)

    • width too large??

    • no p exchange for DSDS

c

s

s

c

??

PRL 93, 041801

M(h J/y)


Y 3940 what is it cont d1
Y(3940): What is it (cont’d) ?

  • cc-gluon hybrid?

    • predicted by QCD,

    • decays to DD and DD* are suppressed

      (“open-charm” thresh = mD + m D** = 4.3 GeV)

    • large hadron+J/y widths are predicted

    • masses expected to be 4.3 ~ 4.4 GeV (higher than what we see)

c

c

Horn & Mandula PRD 17 898 (1974) + (many) others


Summary
Summary

  • X(3872):

    • JPC established as 1++

    • cc component is small (≤ few %)

    • all properties consistent with a D0D*0 bound state

u

c

a non-standard meson

u

c

  • Y(3940):

    • No obvious cc assignment

    • tetraquark seems unlikely

    • cc-gluon hybrid?

c

c

?????

  • - Lots to do:

  • determine JPC ; find other modes (DD*, DsDs, …?)




E e b b k x 0

Jon Coleman

Moriond-QCD

March 2005

e+e-B+B- K-X0

244 fb-1

  • Can measure absolute

    B.F.’s of B-K-X0

J/y

Lower limit on BF(XJ/ypp) > 4.3%

@ 90% C.L

cc2

cc1

cc0

Very clear J/y and hc signals

N J/y=258+- 42

N hc =266 +-42

  • cc2,cc0<<cc1

  • X(3872) production much lower than for other Charmonium states:

  • can set lower limit on B.F.


M g j y look back plot
M(gJ/y) look-back plot


Fit cos q l p with 1 mc
Fit cosqlp with 1++ MC

c2/dof=11.9/9

|cosqlp|


ad