Download - Marek Karliner
Marek Karliner
with B. Keren-Zur, H.J. Lipkin, J. Rosner and N. Tornqvist
arXiv:1109.3472
From to , BINP Novosibirsk, 20 Sep. 2011
New States with Heavy Quarks
M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011 2
Outline
• spin-spin interaction between quarks – “color magnetic”
• same constituent quark masses in mesons and baryons
• known baryons + mesons predictions for new heavy baryons: magnetic moments & masses
• apps to heavy exotic QQqq mesons predictions for Belle
• Belle 5/2001: two Z_b(I=1) exotic mesons ~@ B+B*, B*+B*
additional, more deeply bound states with I=0
M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
Constituent Quark Models (CQM)• QCD describes hadrons as valence quarks
in a sea of gluons and q-qbar pairs.• at low E, χSB
• quark constituent mass • hadron can be considered as a bound
state of constituent quarks.• Sakharov-Zeldovich formula:
• the binding & kinetic energies “swallowed” by the constituent quarks masses.
i
imM
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M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
Color Hyperfine (HF) interaction • 1st correction – color hyperfine
(chromo-magnetic) interaction
• A contact interaction• Analogous to the EM hyperfine interaction –
a product of the magnetic moments.
• In QCD, SU(3) generators take the place of the electric charge.
( ) 2HF em i jij i j i j
i j
V e r rmm
jiji
jijiij
QCDHF rrmm
vV
0
ji
ijHF
ii VmM
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M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
Constituent Quark Model:caveat emptor
• a low energy limit, phenomenological model
• still awaiting derivation from QCD
• far from providing a full explanation of the hadronic spectrum, but it provides excellent predictions for mass splittings and magnetic moments
• assumptions:• HF interaction considered as a perturbation • does not change the wave function• same masses for quarks inside mesons and baryons. • no 3-body effects. 5
M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
constituent quark mass ratios• example II:
• extracting quark masses ratio:
s
c
cu
cu
su
su
DD
KK
m
m
rmm
v
rmm
v
MM
MM
0
0
4
4
*
*
rmm
v
rmm
vMM
su
su
KsuKsusu
suKK
0
0
4
**
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M. Karliner, New States with Heavy QBINP Novosibirsk, 20/9/2011
s
u d
color hyperfine splitting in baryons
• The Σ (uds) baryon HF splitting:– Σ*: total spin 3/2 -
u and d at relative spin – 1– Σ : isospin – 1
• Symmetric under exchange of u and d• u and d at relative spin – 1
• the ‘ud’ pair does not contribute to the HF splitting dudu
*
ij
su
su rmm
vMM
06*
s
u d
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M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
Quark mass ratio from HF splittings in mesons and baryons
New type of mass relations with more heavy flavors
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M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
Similar relation for bottom baryons prediction for mass
(MK & Lipkin, hep-ph/0307243)
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new result from CDF atHadron 2011: 193 MeV
M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
also prediction for spin splitting between and
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new result from CDF atHadron 2011: 20 MeV
M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
Magnetic moments of heavy baryons
•
• mag. moments determined by s,c,b moments
• quark mag. moments proportional to their
chromomagnetic moments
DGG: (=EXP)
challengeto EXP !
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Predicting the mass of baryonsQ
Q: Qsd or Qsu. (sd), (sd) in spin-0
mass given byQ
Can obtain (bsd) mass from (csd) + shift in HF:
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M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
several options for obtaining from data:
MeV
MeV
MeV
• The Ξ (Qsq) baryons contain an s quark
• Q mass differences depend on the spectator
• optimal estimate from mesons which contain both s and Q:
Q
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Predictions for other bottom baryonswith B.Keren-Zur, H.J. Lipkin and J.L. Rosner
:
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Work in progress:
•
•
•
•
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M.K. @DIS’09: “D0: Ω_b=6165 +/- 10 (stat) +/- 13(syst.) --- wrong”
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Open challenges for color hyperfine interaction:
• doubly heavy baryons: ccq, bbq SELEX: huge isosplitting ccu-ccd =17 MeV !?...
• b mass: Upsilon(1S)- b (BaBar, CLEO) too large?
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• a menage a trois is very different from an ordinary family…
• similarly, exotic hadrons with both q-q and q-qbar pairs have important color-space correlations that are completely absent in ordinary mesons and baryons.
• when both present, need to keep in mind that q-qbar interaction is much stronger than q-q interaction
color structures that are totally different from those in normal hadrons
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unusual experimental properties of (Q Q qbar qbar) and (Q Qbar q qbar) tetraquarksuntil 5/2011:leading tetraquark candidate: X(3872)Seen in With very high stats by Belle, BaBar and CDFM[X(3872)] = M(D) + M(D*) = 1865 + 2007 to within 1 MeV!
b-quark analogue(s)?
TH: for sufficiently heavy Q-s, tetraquarks might bebelow two meson threshold: (b qbar bbar q) below B Bbar(b qbar cbar q) below B Dbar
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crucial difference vs. ordinary mesons: can form a color configurationwhich has much stronger binding than
some of these states have exotic electric charge, e.g.
their decays have striking experimental signatures: monoenergetic photons and/or pions, e.g. with I=0 above threshold can decay into via isospin violation,
or electromagnetically into
both very narrow!
M. Karliner, New States with Heavy Q BINP Novosibirsk, 20/9/2011
Unique signal for bbqq and bbqdouble bottom baryons and bb tetratqaurks
_ _
• b c c s J/ψ s_
so bbq J/ψ J/ψ (ssq) J/ψ J/ψ Ξ
similarly bbqq J/ψ J/ψ (ssqq) J/ψ J/ψ K K ___ _
With all final state hadrons coming from the same vertex
Unique signature but v. low rate. Challenge & opportunity for LHCb !
and bbqq__
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0802.0649 [hep-ph], Lipkin & M.K.: Enhancement due to mediation by tetraquark T_bb:
B B*-bar (b-bar b u dbar)
2008: Belle reportedanomalously large BR (2 orders of mag.)
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Tornqvist, Z. Phys. C61,525 (1993):
Heavy-light Qq mesons have I=1/2 they couple to pions deuteron-like meson-meson bound states, “deusons” via pion exchange:
(I=0) at threshold X(3872) ! S-wave I=1 attraction x3 weaker than I=0 no I=1
What about B B-bar* analogue ?...
Alternative (complementary ?) desc. as “molecule”
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B B* vs D D*:-- same attractive potential -- much heavier, so smaller kinetic energy expect and I=1 states near threshold
seen by Belle !!!
I=0 binding much stronger I=0 states expected 40-50 MeV below threshold
EXP signature:Z_b(I=0) (ns) + -
Z_b(I=0) B B-bar via EM B* B , E()=46 MeV
LHCb!
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_b heavier, with I=1 stronger binding via
deuteron-like J=1, I=0 bound state: “beautron”
exp. signature:
(_b _b) _b _b
(_b) = 4.3+-3 MeV, (_b) = 9.2+-3 MeV
so might be visible
should be seen in lattice QCD
- +
?
• consitituent quark model with color HF interaction
_b, _b, _b masses predicted to 3MeV
• challenge for theory: derivation from QCD
• prediction:
• QQqq tetraquarks: new color structures,
unique exp. signatures
• prediction for peaks just seen by Belle
• new I=0 exotic states below threshold:
BB*,B*B*, _b _b , …
Summary
M. Karliner, New States with Heavy Q38
BINP Novosibirsk, 20/9/2011
M. Karliner, New States with Heavy Q
BINP Novosibirsk, 20/9/2011
Backup slides
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M. Karliner, New States with Heavy Q
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M. Karliner, New States with Heavy Q
BINP Novosibirsk, 20/9/2011
constituent quark mass differences
• example I: quark mass differences from baryon mass differences:
dsHF
usHF
udHF
sdu
dcHF
ucHF
udHF
cdu
VVVmmm
VVVmmm
MMc
sc mm 0
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difference of effective quark
masses is the same in
in mesons and baryons
but depends on the spectator quark
“how much you weigh depends
on who your neighbors are”
challenge to npQCD
MK & Lipkin, hep-ph/0307243
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M. Karliner, New States with Heavy Q
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Testing confining potentials
through meson/baryon HF splitting ratio B. Keren-Zur, hep-ph/0703011 & Ann. Phys
• from constituent quarks model can derive:
• depends only on the confinement potential and quark mass ratio
• can be used to test different confinement potentials
baryonsu
mesonsuKK
rr
rr
MM
MM
3
4
*
*
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M. Karliner, New States with Heavy Q
BINP Novosibirsk, 20/9/2011
• 3 measurements (Q = s,c,b)
• 5 potentials:• Harmonic oscillator• Coulomb interaction• Linear potential• Linear + Coulomb• Logarithmic
Testing confining potentials
through meson/baryon HF splitting ratio
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Hyperfine splitting ratio from potential models vs experiment
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BINP Novosibirsk, 20/9/2011
Effective meson-baryon supersymmetry
• meson: Q qbar baryon: Q qq
• in both cases: valence quark coupled to
light quark “brown muck” color antitriplet,
either a light antiquark (S=1/2) or a light diquark (S=0,S=1)
• Effective supersymmetry:
• m( ) – m( ) independent of quark flavor (u,s,c,b) !
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M. Karliner, New States with Heavy Q
BINP Novosibirsk, 20/9/2011
• for spin-zero diquarks:
• need to first cancel the HF interaction contribution to meson masses:
• for spin-one diquarks need to also cancel HF contribution to baryon masses:
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M. Karliner, New States with Heavy Q
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Summary of Ξ mass predictions b
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