Belle

1
Belle

• Hawaii activities in Belle
• New particles in BES Belle
• S. L. Olsen

2
Belle highlights 2002-03

• 1st measurement of f2 from B?pp-
• 1st observation of B?Kll-
• Discovery of a new charmonium state
• 1st measurement of f3 (B?KD0 Dalitz plot)
• Hint of new physics in B?fKS
• Measurement of Br(B?p0p0)
• 1st radiative charm decay D?fg

SM
Belle has submitted/published 70 papers (30 since
August 2002)
3
Papers primarily from Hawaii group

• New charmonium state
• (hep-ex/0309032) S.-K. Choi, S.L. Olsen et al.,
• B?DCP K
• (hep-ex/0304032) S.K. Swain, T.E. Browder et al.,
  (accepted by PRD)
• B?B mixing with B?Dp (partial recon)
• PRD 67 092004 (2003) Y.H. Zheng, T.E. Browder et
  al.,
• B?hcK 1st observation
• PRL 90, 071801 (2003) F. Fang, et al.,
• B?hh
• PRD 66, 092002 (2002) B.C.K. Casey, et al.,
• hc discovery
• PRL 89, 102001 (2002) S.-K. Choi, S.L. Olsen, et
  al.,
• B?ppK 1st observation (PRL --- F. Fang)
• ACP for B?hh- (PRD --- B. Casey)
• B-?K1(1270) J/y (PRL --- S.-K. Choi, S.L. Olsen))

4
Hawaii service in Belle

• TOF system (essential for all CPV studies)
• Calibration Mike Jones
• Reconstruction Mike Peters
• Tracking (essential to all analyses)
• Kalman filter (fitting) Karim Trabelsi
• KS?pp- selection Fang Fang
• Trigger
• Level 0 Hulya Guler
• Level 1.5 (SVD-CDC matching) Kirika Uchida
• Background simulations (for SVD upgrade)
• Spent particles Karim Trabelsi
• Synchrotron radiation Sanjay Swain
• MC
• generator tuning Rolf Seuster
• Event generation Eric Dodson

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Hawaii service in Belle (contd)

• Utilities
• Run-by-run CM energy calibration Sanjay Swain
• N(BB) determination Sanjay Swain
• General event selection criteria Brendan Casey
• SVD upgrade
• Electronics Gary Varner
• Opto-Mechanical Marc Rosen
• Software Karim Trabelsi Kirika Uchida
• Upgrades
• DAQ Gary Varner Yang Heng Zheng
• Pixels Fang Fang
• Administrative
• Analysis coordinator Tom Browder
• Co-spokesperson S. Olsen

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Other analyses underway

• CPV in B?Dr (Trabelsi Peters)
• CPV in B?hc KS (Fang)
• CPV in B?DCPK (Swain, Kent)
• Charm fragmentation (Seuster)
• B?Kpp J/y B? Kppy (Guler)
• Search for 1hc1 (i.e. 1Pc1 cc state) (Fang)
• B?h(980)X (Uchida)
• New particle searches (Olsen)

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New particles in Belle BES

• New state in B?K pp-J/y
• MppJ/y 3872 MeV ( MD MD)
• inconsistent with a cc state
• Low mass pp enhancement in
• J/y?g pp (BES)
• B? pp h (Belle)

J/???pp
???
B?Kpp
m(pp)
???
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New state in B?K pp-J/y
9
charmonium levels
These are narrow if MltMDMD
DD threshold
1Dc2
y(3Dc1)
m?
3Dc3
3Dc2
DD threshold
y

1h1?
hc
we found this last year in B?K KsKp
hc
cc0,1,2
J/y
hc
cc level diagram
10
B?K KSKp (hc studies)
Mbc for 40 MeV KSKp mass bins
what is this?? ?Dc2?ggg?
hc region
veto hc
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Look for it in B?K pp-J/y(less background,
better resolution) B?K gcc1

• 3Dc2 ?pp J/y g cc1 ? allowed
• G(g cc1 ) gt 5 G(pp J/y)
• 1Dc2 ?pp J/y g cc1 ? not allowed

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M(pp- ll- ) M(ll- )
y?ppJ/y
?
13
Mbc for 10 MeV M(ppJ/y) bins
X?ppJ/y signal!!
y?ppJ/y
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Magnify signal region
15
DE plots shows similar signal
X?ppJ/y signal
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3-d unbinned fit to y region
(B?K y ? K ppJ/y)
Ny 489 23 events
DE
Mbc
MppJ/y

• DE-1.96 0.4
• s(DE)11.6 0.4
• f_tail 3.6 1.5

• Mbc5279.1 0.1
• s(Mbc)2.6 0.1

• MppJ/y3685.5 0.2
• s(Mppj/y)3.3 0.2

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3-d unbinned fit to X(3872) region
NX 35.7 6.8 events
MppJ/y
DE
Mbc

• DE-1.96 (fixed)
• s(DE)11.6 (fixed)
• f_tail 3.6 (fixed)

• Mbc5279.1 (fixed)
• s(Mbc)2.6 (fixed)

• MppJ/y3871.5 0.5
• s(Mppj/y)2.5 0.5

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reference mass to y
MX Mmeas(ppJ/y) Mmeas(y) MPDG(y) MX
3872 0.6 (stat) 0.5 (syst) MeV
This comes from comparing Mmeas(y) with PDG value
BW fit G 1.4 0.7 MeV lt 2.3 MeV _at_ 90 CL
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M pp- tends to peak near limit
background estimated from Mbc-DE sidebands
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r?pp bkgd fits pretty well
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Look for X(3872)?gcc1 ( cc1 ?g J/y)
an allowed E1 transition should be gt 5 ?
X?ppJ/y (Eichten, Lane Quigg)

• Select B-?K- g g J/y
• K- and J/y same as before
• Eggt40 MeV plus p0 veto
• 15 lt M gJ/y-Mcc1lt10MeV

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Do 2-d (Mbc and Mgcc1) fits
y region
Nevts 34.1 6.9 4.1 events expect 26 4
events
(y?gcc1? gJ/y)
Mgcc1
Mbc
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Mbc and Mgcc1 fits to X(3872) region
No signal !!
Mbc
Mgcc1
NX 3.7 3.7 2.2 events (lt9.2 events _at_ 90
CL)
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Limit on G(X?gcc1)
G(X?gcc1)/ G(X?ppJ/y) 0.35 0.36 0.21 lt
0.89 _at_ 90 CL
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Summary

• we see a 10s signal for B? K X where
• X? pp-J/y,
• MX 3872.0 0.6 0.5 MeV Glt2.3 MeV (90CL)
• G(X?gcc1)/G(X? pp-J/y) lt 0.89 (90CL)
• hep-ex/0309032 ? PRL
• is this the 3D2 cc charmonium state?
• Mass is too high (3872 vs 3810 MeV)
• G(X?gcc1)/G(X? pp-J/y) too small (lt0.89 vs gt
  5)
• angular analysis is necessary (but hard).
• MX MD0 M D0. 3871.3 1.0 MeV
• could it be a D-D bound state?

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Low mass pp enhancement in J/y?g pp (BES)
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Use BESIIs 58M J/y decays
Select J/y?gpp
J/y?gpp

• 4-C kinematic fit
• dE/dx for proton id
• non-pp bkg small
• main bkg from J/y?p0pp

????

• J/y?ghc hc? pp
• (calibration reaction)

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Study J/y?p0pp bkg with MC data
J/y?p0pp (data)
three-body phase space Monte Carlo
J/y?p0pp?gpp (MC)
M(pp)-2mp (GeV)
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The signal is real

• Really protons and antiprotons
• dE/dx pid verified by BSC response
• Not bkgd from J/y ? hadrons
• No hint of peaking in J/y ?p0 pp data
• Not a QED background
• Eg pulls are symmetric
• cosqg distribution not peaked
• not seen in off-J/y data

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Fit to data
fitted peak location
J/y?gpp
acceptance weighted BW
M1859 3 5-25 MeV G lt 30 MeV (90 CL)
c2/dof56/56
0
0.1
0.2
0.3
M(pp)-2mp (GeV)
3-body phase space
acceptance
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Is Mpeak really less than 2mp?
weight events by q0/q (i.e remove threshold
factor)
No turnover at threshold ?peak mass must be lt2mp
M(pp)-2mp (GeV)
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P-wave fit??
OK!!
M1876 3 ?-?? MeV G lt 30 MeV (90 CL)
M2mp!!
c2/dof59/56
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D-wave fit??
NG!!
M1885 ? ?-?? MeV G lt 30 MeV (90 CL)
c2/dof1405/56
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cosqg distribution
1cos2qg (expected for J/y?g0-)
M(pp)lt1.9 GeV
sin2qg
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include possible biases as (asymmetric)
systematic errors (at least for now)
M1859 3 5-25 MeV G lt 30 MeV (90 CL)
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Summary

• A large enhancement seen near 2mp in the Mpp
  distribution for J/y?gpp decays.
• Not apparent in J/y?popp decays
• Not consistent with any PDG meson state
• If it is an S-wave resonance
• Mpeak is below 2mp (M1859 3 5 25 MeV)
• full width is narrow (Glt30 MeV)
• dN/dcosqg consistent with JPC 0-
• PRL 91, 022001 (2003)

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Comments

• peak near but below 2mp a pp bound state?
• narrow width why so long-lived?
• similar patterns seen in baryon-antibaryon
  systems produced in B meson decays
• B?ppK B?ppD B?pLp B?pLcp

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Belle sees low-mass pp systems in B decays
B?ppp
B?ppK
F. Fang
M
M
pp
pp
B?ppK
B?ppKS
M
M
pp
pp
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low-mass pp peaks in all (?) B?baryon decays
B?D0pp
M
pp
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Strange charmed systems
B-?pLcp-
B0?pLp-
M(Lp) (GeV)
(in these cases, the peaking doesnt seem to be
right at threshold)
M(Lcp) (GeV)
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hh bound states (hadronium)??
There is lots lots of literature about this
possibility
deuteron
hadronium
attractive nuclear force
attractive force??

n
h
h
p
p
loosely bound 3-q color singlets with Md 2mp- e
loosely bound 3-q or q-q color singlets with Mb
2mp-d
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hadronic moleculesa new spectroscopy?