The charm content of jets at the CERN p p collider

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5593591

Ikeda, Makoto

The charm content of jets has been measured in proton-antiproton collisions at {radical}s = 630 GeV using the UA1 detector at the CERN collider. This measurement was used to test QCD and in particular to confirm the large charm cross section predicted for O ({alpha}{sub s}{sup 3}) processes. the data used for the analysis was obtained by the use of a jet trigger in 1984 and 1985. The integrated luminosity of the sample was 618 nb{sup {minus}1}. The decay mode, D{sup {asterisk}+} {yields} D{sup 0} {pi}{sup +} {yields} K {minus} {pi}{sup +}{pi}{sup +} was used to identify the D{sup {asterisk}{plus minus}} meson. In a sample of jets chosen to enrich the D{sup {asterisk}{plus minus}} signal, a peak of 3 standard deviation significance in the mass difference spectrum, {Delta}M = M(K{pi}{pi}) was observed. The peak was centered at 145.3 {plus minus} 0.2 MeV/c{sup 2} in good agreement with the world average value. The number of D{sup {asterisk}{plus minus}} per jet was measured for a sample of 8.6 {sup {asterisk}} 10{sup 3} jets with average E{sub T} of 43 GeV. The resulting signal for N(D{sup {asterisk}{plus minus}})/N(jet) was 0.11 {plus minus} 0.05 {plus minus} 0.02 for p(D{sup {asterisk}{plus minus}}) > 5 GeV. Approximately 70% of the jets are due to gluons. The corresponding number of c{bar c} pairs per gluon jet is consistent with the QCD prediction for gluon fragmentation to charm quark pairs. The distribution in z(D{sup {asterisk}{plus minus}}) = p(D{sup {asterisk}{plus minus}})/p(jet) is soft with {l angle}z{r angle} = 0.02 for z > 0.1, consistent with charm production through gluon fragmentation.

• Research Organization: California Univ., Riverside, CA (United States)
• OSTI ID: 5593591
• Country of Publication: United States
• Language: English

Related Subjects

662320 -- Neutrino Interactions-- (1992-)
662340* -- Hadron Interactions-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BARYON-BARYON INTERACTIONS
BARYONS
BOSONS
CHARM PARTICLES
CHARMED MESONS
CROSS SECTIONS
DATA ANALYSIS
DECAY
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
FIELD THEORIES
GEV RANGE
GEV RANGE 100-1000
GLUONS
HADRON-HADRON INTERACTIONS
HADRONS
INTERACTIONS
JET MODEL
MASS DIFFERENCE
MATHEMATICAL MODELS
MESONS
NUCLEON-ANTINUCLEON INTERACTIONS
PARTICLE DECAY
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE PRODUCTION
PARTICLE PROPERTIES
POSTULATED PARTICLES
PROTON-ANTIPROTON INTERACTIONS
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
QUARKS
TESTING