New types of sub-atomic particles

1
New types of sub-atomic particles

• Stephen L. Olsen
• University of Hawaii

d
u
u
d
s
u
c
u
c
c
c
2
History(hadrons)

• 1930s proton neutron
• ..all we need???
• 1950s ?,?,?,?,?,?
• Had I foreseen that, I would have
• gone into botany Fermi
• 1960s The 8-fold way
• 3 quarks for Müster Mark
• 1970s add charmed particles
• 1980s beauty
• 1990s (finally?) top

chadwick
Fermi
Gell-Mann
Zweig
Richter
Ting
Lederman
Peters
Jones
3
Hadron zoo
mesons
baryons
4
Quarks restore economy( rescue future Fermis
from Botany?)
3 quarks
( 3 antiquarks)
u2/3
u-2/3
M. Gell-Mann
d-1/3
s-1/3
d1/3
s1/3
Baryons qqq
Mesons q
q
Zweig
u2/3
u2/3
p
u2/3
p
d-1/3
d1//3
u-2/3
u-2/3
u-2/3
p
p-
d1/3
u2/3
5
Fabulously successful, but

• quarks are not seen
• why only qqq and qq combinations?
• What about spin-statistics?

6
W-
s-1/3
s-1/3
s-1/3
2 of these s-quarks are in the same quantum state
Das ist verboten!!
7
The strong interaction charge of each quark
comes in 3 different varieties
Y. Nambu
O. Greenberg
W-
s-1/3
s-1/3
s-1/3
the 3 s-1/3 quarks in the W- have different
color charges evade Pauli
8
QCD Gauge theory for color charges
Nambu Gell-Mann Fritzsch
generalization of QED
QED
er eb eg
QCD
scalar charge e
isovector charge
QED gauge Xform
QCD gauge Xform
? ? ? i e A
? ? ? i a li Gi
1 vector field (photon)
8 vector fields (gluons)
eight 3x3 SU(3) matrices
9
Attractive configurations
eijk eiejek i ? j ? k
dij ei
ej
same as the rules for combining colors to get
white add 3 primary colors or add
colorcomplementary color
quarks eiejek ? color charges
antiquarks ? anticolor charges
ej
ei
ek
Hence the name Quantum Chromodynamics
10
Difference between QED QCD

• QED photons have no charge
• QCD gluons carry color charges
• gluons interact with each other

11
QED??QCD difference
Coupling strength
a
distance
12
Test QCD with 3-jet events( deep inelastic
scattering)
as
gluon
rate for 3-jet events should decrease with Ecm
13
running as
Why are these people smiling?
14
Probe QCD from other directions

• non-qq or non-qqq hadron spectroscopies
• Pentaquarks
• e.g. an S1 baryon
• (only anti-s quark has S1)
• Glueballs
• gluon-gluon color singlet states
• Multi-quark mesons
• qq-gluon hybrid mesons

d
u
u
d
s
u
c
u
c
c
c
15
Pentaquarks
Seen in many experiments
but not seen in just as many others
Belle
BES
BaBar
CDF
High interest 1st pentaquark paper has 500
citations
16
Experimental situation is messy(many
contradictory results)
NA49 pp _at_ Ecm17 GeV (fixed tgt) (PRL92, 052301
237 citations!)
COMPASS mp _at_ Em 160 GeV (fixed tgt)
X(1862) qqssd
1862 2 MeV FWHM 17 MeV ? 5.6
100s of X(1530)s but no hint of
X(1862) hep-ex/0503033
17
Pentaquark Scoreboard
Positive signals
Negative results
Also Belle Compass L3
Yes 17
No 17
18
Existence of Pentaquarksis not yet established
19
This talk search for non-standard mesons with
hidden charm
u
c
u
c
c
c
(i.e containing c c)

• standard cc mesons are
• best understood theoretically
• narrow non overlapping
• c c systems are commonly produced in B meson
  decays.

c
c
Vcb
b
W-
cosqC
s
CKM favored
20
Thanks to KEKB we have lots of B mesons(gt1M BB
pairs/day)
gt1fb -1/day
Design 10 34
21
Is the X(3872) non-standard?

• B?K pp-J/y

y?pp-J/y
X(3872)?pp-J/y
M(ppJ/y)
S.K. Choi et al PRL 91, 262001
22
Its existence is well establishedseen in 4
experiments
CDF
9.4s
11.6s
X(3872)
D0
X(3872)
hep-ex/0406022
23
Is it a cc meson?
Could it be one of these?
3872 MeV
These states are already identified
24
no obvious cc assignment
hc hc cc1 y2 hc2 y3
M too low and G too small
angular distn rules out 1-
3872
G(gJ/y) way too small
G(gcc1) too smallM(pp-) wrong
pp hc should dominate
G( gcc2 DD) too small
SLO hep-ex/0407033
25
go back to square 1

• Determine
• JPC
• quantum numbers
• of the X(3872)
• with minimal assumptions

26
JPC possibilities (for J 2)
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
27
JPC possibilities0-- ruled out JP0,1- 2
unlikely
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
28
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

29
Search for X(3872)?g J/y
30
Kinematic variables
B?K gJ/y

Ecm/2
e
e-
B? ?B
?(4S)
Ecm/2
DE
CM energy difference
B?K gJ/y
Beam-constrained mass
Mbc
31
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 (gt5s significance)
Bf(X?gJ/y) Bf(X?ppJ/y)
0.14 0.05
32
Evidence for X(3872)?pp-p0 J/y(reported last
summer hep-ex/0408116)
12.4 4.2 evts
B-meson yields vs M(pp-p0)
Br(X?3pJ/y) Br(X?2pJ/y)
Large (near max) Isospin violation!!
1.0 0.5
33
C1 is established

• B?g J/y only allowed for C1
• same for X?wJ/y (reported earlier)
• M(pp) for X?pp-J/y looks like a r

34
JPC possibilities (C-1 ruled out)
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
35
Angular Correlations
r
Jz0
J0
X3872
J0
K
z
J/y
36
Strategy for each JPC, find a distrib ?0if we
see any events there, we can rule it out
Rosner (PRD 70 094023) Bugg (PRD 71
016006) Suzuki, Pakvasa (PLB 579 67)
37
Use 250 fb-1 ? 275M BB prsexploit the
excellent S/N
X(3872)?pp-J/y
y?pp-J/y
Signal (47 ev)
Sidebands (114/10 11.4 ev)
38
0-
c2/dof18/9
0- sin2q sin2y
q
cosq
c2/dof34/9
y
cosy
safe to rule out 0-
39
0
In the limit where X(3872), pp, J/y rest frames
coincide dG/dcosqlp ? sin2qlp
qlp
c2/dof 41/9
cosqlp
rule out 0
40
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!
41
JPC possibilities (0- 0 ruled out)
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
42
Fits to the M(pp)Distribution
J/y
X?rJ/y in P-wave has a q3 centrifugal barrier
q
X
r
q
43
M(pp) can distinguish r-J/y S- P-waves
P-wave c2/dof 71/39
S-wave c2/dof 43/39
(CL0.1)
(CL 28)
q roll-off
q3 roll-off
Shape of M(pp) distribution near the kinematic
limit favors S-wave
44
Possible JPC values (J- ruled out)
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
45
Search for X?D0D0p0
46
Select B?KD0D0p0 events
D0?D0p0?
M(D0D0p0)
DE
DE
11.33.6 sig.evts (5.6s) Bf(B?KX)Bf(X?DDp)2.20
.70.4x10-4
Preliminary
47
X?DDp rules out 2

• 1 DD in an S-wave ? q
• 2 DDp in a D-wave ? q5

Strong threshold suppression
48
Possible JPC values (2 ruled out)
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
1
1
49
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)lt0.1
• BaBar measurement
• Bf(X?ppJ/y)gt4

3872
- G(cc1?gJ/y) / G(cc1?ppJ/y) Theory
40 Expt 0.14 0.05
cc1 component of the X(3872) is few
50
Intriguing fact

• MX3872 3872 0.6 0.5 MeV
• mD0 m D0 3871.2 1.0 MeV

lowest mass charmed meson
lowest mass spin1 charmed meson
X(3872) is very near DD threshold. is it somehow
related to that?
51
hh bound states (hadronium)?
There is lots of literature about this possibility
N. Tornqvist hep-ph/0308277
deuteron
hadronium (dueson)
attractive nuclear force
attractive force??
c
c
p
n
D
D
p
p
u
u
2 loosely bound qqq color singlets with Md
mpmn- e
2 loosely bound qq color singlets with M mD
mD - d
52
X(3872) D0D0 bound state?

• JPC 1 is favored
• M mD0 mD0
• Maximal isospin violation is natural ( was
  predicted)
• I1 Iz 0gt 1/?2(DD-gt D0D0gt)
• I0 Iz 0gt 1/?2(DD-gt - D0D0gt)
• ? D0D0gt 1/?2(10gt - 00gt)
• G(X?gJ/y) lt G(X?ppJ/y) was predicted

Tornqvist PLB 590, 209 (2004)
Equal mixture of I1 I 0
Swanson PLB 588, 189 (2004)
Swanson PLB 598, 197 (2004)
53
X(3872) conclusion

• Not a cc state
• Matches all(?) expectations for a D0D0 bound
  state

C
C
u
c
u
1st clear example of a non-qq meson
c
54
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 ? hadronsJ/y

B?K h J/y
B?K p J/y
B?K w J/y
55
B?K wJ/y in Belle
Y(3940) M3940 11 MeV G 92 24 MeV
Mbc
Mbc
Mbc
S.K. Choi et al hep-ex/0408126?PRL
56
Y(3940) What is it?

• 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
57
Y(3940) What is it (contd)?

• another tetraquark?
• M 2mDs
• not seen in Y?hJ/y
• (h contains ss)
• width too large??
• need to search for Y(3949)?DSDS

c
s
s
c
??


PRL 93, 041801
M(h J/y)
58
Y(3940) What is it (contd) ?

• cc-gluon hybrid?
• predicted by QCD,
• decays to DD and DD are suppressed
• large hadronJ/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)
59
Summary

• X(3872)
• JPC established as 1
• cc component is small ( few )
• all properties consistent with a D0D0 bound
  state

u
c
1st unambiguous example of 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, ?)
60
Mahalo
61
Back-up slides
62
Difference between QED QCD

• QED photons have no charge
• QCD gluons carry color charges
• gluons interact with each other

63
Vacuum polarization QED vs QCD
2nf
11CA
in QCD CA3, this dominates
64
QED??QCD difference
Coupling strength
a
distance
65
Testing the Standard Model

• QCD X Electro-Weak X QED

W, Z t masses Z width sin2qW Asymmetries Cross-
sections
decrease in aswith distance
Lamb-shift g-2 Atomic spectra
66
Tests of QED and EW sectors
Electro-Weak sector (tested _at_ 0.01 level)
QED (tested _at_ ppb)
Example (g-2)/2electron Expt 1,159,652,188.4(
4.3)x10-12 Theory 1,159,652,201.4(28)x10-12
67
M(gJ/y) look-back plot
68
Another one?

• ee- ?J/y X
• gt4s)peak at M3940?11 MeV
• N148?33 evts
• Width consistent w/ resolution
• ( 32 MeV)

hc


hc
cc0
hc
What is it? cc0 ? hc ??


69
Look at ee-?J/y D(D())

• Reconstruct a J/y a D
• use D0?K-p D?K-pp
• Determine recoil mass

70
Look at M(DD())
3940 MeV
9.9 3.3 evts (4.5 s)
DD
cc0 ?DD

DD
4.1 2.2 evts (2.1 s)
hc ?DD

71
Other hadronium states?
fitted peak location
J/y?gpp in the BES expt
J.Z.Bai PRL 91,022001(2003)
3 5 -10 -25

M1859 MeV/c2 G lt 30 MeV/c2 (90 CL)
c2/dof56/56
0
0.1
0.2
0.3
M(pp)-2mp (GeV)
acceptance