Search for theηc′(21S0)charmonium resonance

10 August 2001

journal article
research article
Published by American Physical Society (APS) in Physical Review D

Vol. 64 (5) , 052003
https://doi.org/10.1103/physrevd.64.052003

Abstract

We report on a search by Fermilab experiment E835 for the

η_{c}^{'}

(2^{1} S_{0})

charmonium resonance in the process

\bar{p} \vec{p} η_{c}^{'} \to γ γ .

No signal was observed and, based on 34

{pb}^{- 1}

integrated luminosity, we determine the following upper limits (90% confidence level) to the product of the branching ratios for a resonance mass in the region 3575–3660

MeV {/ c}^{2} :

B r (η_{c}^{'} \to \bar{p} p) \times B r (η_{c}^{'} \to γ γ) < 12.0 \times 10^{- 8}

for

Γ = 5

MeV;

< 5.9 \times 10^{- 8}

for

Γ = 10

MeV;

< 4.8 \times 10^{- 8}

for

Γ = 15

MeV. Combining the present data with those of the predecessor experiment, E760, the upper limits become

8.0 \times 10^{- 8},

5.0 \times 10^{- 8},

and

4.5 \times 10^{- 8},

respectively. In the restricted region 3589–3599

MeV {/ c}^{2},

where a candidate was reported by the Crystal Ball experiment, we obtain the following limits from the combined E760–E835 experiments:

B r (η_{c}^{'} \to \bar{p} p) \times B r (η_{c}^{'} \to γ γ) < 5.6 \times 10^{- 8}

for

Γ = 5

MeV;

< 3.7 \times 10^{- 8}

for

Γ = 8

MeV. A comparison of these with other experimental results is presented.

Keywords

This publication has 21 references indexed in Scilit:

The threshold gas Cherenkov counter of charmonium experiment 835 at Fermilab
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1999
Results from the E835 scintillating fiber detector
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1998
The variable density gas jet internal target for Experiment 835 at Fermilab
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1998
A straw chambers’ tracker for the high rate experiment 835 at the Fermilab accumulator
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1998
Construction and performance of a cylindrical scintillating fiber detector for experiment 835 at FNAL
IEEE Transactions on Nuclear Science, 1997
A pp̄ luminosity monitor for Fermilab experiment E760
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995
The Antiproton Sources: Design and Operation
Annual Review of Nuclear and Particle Science, 1993
A trigger for the Fermilab E760 lead-glass calorimeter
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1991
The E760 lead-glass central calorimeter: design and initial test results
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1991
Observation an an $η_{c}^{'}$ Candidate State with Mass 3592 ±5 MeV
Physical Review Letters, 1982