Observation of a near threshold enhancement in th p anti-p mass spectrum from radiative J / psi ---> gamma p anti-p decays

Bai, J.Z.; Ban, Y.; Bian, J.G.; Cai, X.; Chang, J.F.; Chen, H.F.; Chen, H.S.; Chen, J.; Chen, Jie; Chen, J.C.

doi:10.1103/PhysRevLett.91.022001

Observation of a near threshold enhancement in th p anti-p mass spectrum from radiative J / psi ---> gamma p anti-p decays

BES

Collaboration

•

J.Z. Bai

Mar, 2003

5 pages

Published in:

Phys.Rev.Lett. 91 (2003) 022001

e-Print:

hep-ex/0303006 [hep-ex]

DOI:

PDG:

{{\mathit J / \psi}{(1S)}}

\rightarrow

{{\mathit \gamma}}{{\mathit X}{(1835)}}

\rightarrow

{{\mathit \gamma}}{{\mathit p}}{{\overline{\mathit p}}}

Report number:

SLAC-PUB-9709,
UH-511-1019-03

Experiments:

BEPC-BES

View in:

links

reference search409 citations

Citations per year

Abstract: (arXiv)

We observe a narrow enhancement near 2mp in the invariant mass spectrum of ppbar pairs from radiative J/psi-->gamma ppbar decays. The enhancement can be fit with either an S- or P-wave Breit Wigner fuction. In the case of the S-wave fit, the peak mass is below the 2mp threshold and the full width is less than 30 MeV. These mass and width values are not consistent with the properties of any known meson resonance.

electron positron: colliding beams
electron positron: annihilation
J/psi(3100): electroproduction
J/psi(3100): radiative decay
p: pair production
mass spectrum: (p anti-p)
mass enhancement: (1859)
width
BES
experimental results

References(16)

Figures(0)

The first measurement of the neutron electromagnetic form-factors in the timelike region

A. Antonelli
(
- Frascati
)
,
R. Baldini
(
- Frascati
)
,
P. Benasi
(
- Ferrara U. and
- INFN, Ferrara
)
,
M. Bertani
(
- Ferrara U. and
- INFN, Ferrara
)
,
M.E. Biagini
(
- Frascati
)

et al.

- Nucl.Phys.B 517 (1998) 3-35
•
DOI:
- 10.1016/S0550-3213(98)00083-2

Determination of the electric and magnetic form-factors of the proton in the timelike region

G. Bardin
(
- DAPNIA, Saclay
)
,
G. Burgun
(
- DAPNIA, Saclay
)
,
R. Calabrese
(
- Ferrara U. and
- INFN, Ferrara
)
,
G. Capon
(
- Frascati
)
,
R. Carlin
(
- INFN, Padua and
- Padua U.
)

et al.

- Nucl.Phys.B 411 (1994) 3-32
•
DOI:
- 10.1016/0550-3213(94)90052-3

Anti-proton Annihilations in Deuterium at Rest Into Two Pions: Evidence for $\bar{P} N$ Bound States Near Threshold

D. Bridges
(
- Syracuse U.
)
,
H. Brown
(
- BNL, NSLS
)
,
Inder K. Daftari
(
- Syracuse U.
)
,
R. Debbe
(
- Case Western Reserve U.
)
,
A. Deguzman
(
- Syracuse U.
)

et al.

- Phys.Lett.B 180 (1986) 313-318,
- Phys. Lett. B180 ( 1986) 313-318
•
DOI:
- 10.1016/0370-2693(86)90317-5

Evidence for a bound anti-N N(1870) state produced in the anti-p d ---> p(s) 5pi reaction

- Phys.Lett.B 392 (1997) 229-233
•
DOI:
- 10.1016/S0370-2693(96)01585-7

ARE MESONS ELEMENTARY PARTICLES?

E. Fermi
(
- Chicago U., EFI
)
,
Chen-Ning Yang
(
- Chicago U., EFI
)

- Phys.Rev. 76 (1949) 1739-1743,
- In *Yang, C.N.: Selected Papers 1945-1980*, 122-126
•
DOI:
- 10.1103/PhysRev.76.1739

Dynamical Model of Elementary Particles Based on an Analogy with Superconductivity. 1.

Yoichiro Nambu
(
- Chicago U., EFI
)
,
G. Jona-Lasinio
(
- Chicago U., EFI
)

- Phys.Rev. 122 (1961) 345-358,
- Also in *Lai, C. H. (Ed.): Gauge Theory Of Weak and Electromagnetic Interactions*, 104-117,
•
DOI:
- 10.1103/PhysRev.122.345