Study of the [chi][sub 1] and [chi][sub 2] states produced in [anti p]p annihilations in Fermilab Experiment 760

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7271463

Marques, J L

A study of the [chi][sub 1]([sup 3]P[sub 1]) and the [chi][sub 2]([sup 3]P[sub 2]) states of charmonium formed in anti-proton-proton annihilations is reported in this dissertation. Performed at Fermi National Accelerator Laboratory, Experiment 760 used an internal molecular hydrogen jet target and circulating beam of momentum cooled antiprotons to conduct energy scans of the two resonances. The small momentum spread of the antiproton beam allowed very precise measurements of both the resonance mass and total width to be made. From a sample of 438[sub [chi] 1] and 556 [sub [chi] 2] events the following resonance parameters have been determined: [Gamma][sub [chi]1] = (0.86 [+-] 0.14) MeV, [Gamma][sub [chi]2] = (2.01 [+-] 0.18) MeV, M[sub [chi]1] = (3510.51 [+-] 0.13) MeV/c[sup 2], M[sub [chi]2] = (3556.03 [+-] 0.14) MeV/c[sup 2], [Gamma]([chi][sub 1] [yields] [anti p]p) x BR([chi][sub 1]BR[yields] J/[psi][gamma]) x BR(J/[psi] [yields] e[sup +]e[sup [minus]]) = 1.22 [+-] 0.15 eV, and [Gamma]([chi][sub 2] [yields] [anti p]p) x BR([chi][sub 2] [yields] J/[psi][gamma]) x BR(J/[psi] [yields] e[sup +]e[sup [minus]]) =(1.68 [+-] 0.16) eV. The angular distribution for the reaction [chi][sub 1,2] [yields] J/[psi]+[gamma] [yields] E[sup +]e[sup [minus]]+[gamma] was also studied. For the [chi][sub 1] resonance, from a sample of 360 events, the radiative decay quadrupole amplitude has been found to be a[sub 2] = [minus]0.14 [+-] 0.06. For the [chi][sub 2], from a sample of 1904 events, the radiative decay quadrupole and octupole amplitudes have been found to be a[sub 2] = [minus]0.15 [+-] 0.07 and a[sub 3] = 0.00 [+-] 0.05 respectively. The contribution from helicity zero in the formation process of the [chi][sub 2] has also been measured, B[sup 2][sub 0]=0.02 [sup +0.13][sub [minus]0.02].

• Research Organization: California Univ., Irvine, CA (United States)
• OSTI ID: 7271463
• Country of Publication: United States
• Language: English

Related Subjects

662340* -- Hadron Interactions-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATORS
ANNIHILATION
AXIAL VECTOR MESONS
BARYON-BARYON INTERACTIONS
BASIC INTERACTIONS
BOSONS
CHARMONIUM
CHI1-3510 MESONS
CHI2-3555 MESONS
CYCLIC ACCELERATORS
DECAY
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMILAB ACCELERATOR
HADRON-HADRON INTERACTIONS
HADRONS
INTERACTIONS
MESONS
NUCLEON-ANTINUCLEON INTERACTIONS
PARTICLE DECAY
PARTICLE INTERACTIONS
PROTON-ANTIPROTON INTERACTIONS
QUARKONIUM
RADIATIVE DECAY
SYNCHROTRONS
TENSOR MESONS