Jens Sören LangeJustus-Liebig-Universität GießenPHIPSI19, Novosibirsk26.02.2019

XYZ at Belle

An MSCA-RISE project funded by European Union under grant n.644294

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Outline

3 XYZ States and Confinement | Sören Lange (Giessen) XYZ at Belle | S. Lange | PHIPSI19

Y(4260) IN B DECAYS

4 XYZ States and Confinement | Sören Lange (Giessen) XYZ at Belle | S. Lange | PHIPSI19

BESIII, Phys. Rev. Lett. 118 (2017) 092001

Y(4260)

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Y(4260) in B decays

Even

ts /

50

MeV

Even

ts /

15

MeV

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R. Garg, V. Bhardwaj, J. B. Singh, et al. (Belle Collaboration), arXiv:1901.06470 [hep-ex]

Y(4260) in B decays – NEW Belle RESULTCONTROL SIGNALS Belle, 711 fb–1 (full Belle data)

B+

B0

B+

B0

7 XYZ States and Confinement | Sören Lange (Giessen) XYZ at Belle | S. Lange | PHIPSI19

Factor ~3.3 more data than BaBarNeutral B decays addedNo signal observedUpper limit consistent with BaBar(branching fraction reaches 10–6 level)

R. Garg, V. Bhardwaj, J. B. Singh, et al. (Belle Collaboration), arXiv:1901.06470 [hep-ex]

Y(4260) in B decays – NEW Belle RESULT

B+

B0

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SPIN PARTNEROF Y(4630)

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Belle, Phys. Rev. D91 (2015) 112007

Y(4660)

m(y'p+p–)/GeV

Y(4630)

Belle, Phys. Rev. Lett. 101 (2008) 172001

m(Lc+Lc

–) / GeV

Y(4630)

PDG2018: only Y(4660)

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JPCBarnes, Godfrey, Swanson, Phys. Rev. D72(2005)054026

ηcρ

ηc(2S)ρ

J/yρ

y(2S)ρ

q q

q q

q q

q q

Q Q

q q

J/y f0

y(2S)f0

HADROCHARMONIUMDubynskiy, Voloshin, Phys. Lett. B666(2008)344

X(3872)ηc f0

ηc (2S) f0

Y(4260)

Y(4630)spin partner

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Search for spin partner state of Y(4630)

Y. B. Li, C. P. Shen, et al. (Belle Collaboration), Eur. Phys. J. C 78 (2018) 252

No signal observed. Upper limit:

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ABSOLUTE BRANCHING FRACTION

OF X(3872)

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Total branching fraction not known 100% ?

X(3872) in the PDG 2018

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B+B–Y(4S)

Kaon

Xcc

TAG

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Y. Kato, T. Iijima, et al. (Belle Collaboration), Phys. Rev. D97 (2018) 012005

711 fb–1 (full Belle data set)

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Efficiency small(requires tag side)

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DOUBLE ZcPRODUCTION

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(102 Mill., 158 Mill.)

Search for double Zc production at Belle

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S. Jia, C. P. Shen, C. Z. Yuan, et al. (Belle Collaboration)Phys. Rev. D 97 (2018) 112004

Search for double Zc production at Belle

Data set, in which Zb

(‘) were observed

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Search for double Zc production at Belle

Born cross section in [fb]

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STRANGE PARTNEROF Pc

+ PENTAQUARK

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Search for Ps+

B. Pal, A. J. Schwartz, et al. (Belle Collaboration), Phys. Rev. D 96 (2017) 051102

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Conclusion

● Analyses in Belle still ongoing (although Belle II starting up):● Searches for partner states● Diferent production mechanisms (ISR vs. B decays vs. ϒ decays)● Absolute branching fractions

Thank you.

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BACKUP

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X(4630) 8.2σ

Phys. Rev. Lett. 101(2008)172001, 670 fb–1

e+e–→Λc+Λc

– γISR

Lc → pKs0 , pK−p+ , Lp+

Lc− is tagged by anti-proton (partial reconstruction)

X(4630)

Λc

sidebands

Λc

Λc(2625)

Λc(2595)

Λc(2765)

Λc(2880)

Signalcut

m(Lc+Lc

–) / GeVmRECOIL(Lc+gISR) / GeV

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