Yang, Haijun
Max results
Sort by Reverse order

Showing 10 of 2895 results

Date

Measurement of the Relative Total Hadronic Cross-section R at {PETRA}

The Aachen-DESY-Annecy(LAPP)-MIT-NIKHEF-Beijing collaboration Barber, D. ; Becker, U. ; Boehm, A. ; et al.
Phys.Rev.Lett. 42 (1979) 1113, 1979.
Inspire Record 140059 DOI 10.17182/hepdata.3235

We report the first measurement of the ratio R=(σe+e−→hadrons)(σe+e−→μ+μ−) (with negligible τ-lepton contribution) at a center-of-mass energy s=13 GeV and s=17 GeV, from the just finished electron-positron colliding-beam facility PETRA. The detector, MARK-J, has an approximately 4π solid angle and measures γ, e, μ, and charged and neutral hadrons simultaneously. Our results yield R(s=17 GeV)=4.9±0.6 (statistical) ±0.7 (systematic error), and R(s=13 GeV)=4.6±0.5 (statistical) ±0.7 (systematic error). The ratio R(s=17 GeV)R(s=13 GeV) is 1.08±0.18.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Test of Quantum Electrodynamics at {PETRA} Energies

The Aachen-DESY-Annecy(LAPP)-MIT-NIKHEF-Beijing collaboration Barber, D. ; Becker, U. ; Benda, H. ; et al.
Phys.Rev.Lett. 42 (1979) 1110, 1979.
Inspire Record 140093 DOI 10.17182/hepdata.20817

We report on the measurement of the reaction e+e−→e+e− with a large—solid-angle electromagnetic shower detector at center-of-mass energies s=13 and 17 GeV. Comparison of our results with predictions of quantum electrodynamics shows excellent agreement in both the angular distribution and energy dependence. Values of cutoff parameters are also given.

1 data table
Table 1

No description provided.


Inclusive $\pi^0$ Production Over Large $X_{\perp}$ Transverse and $X_F$ Ranges in 200 GeV/c, 300 GeV/c and 400 GeV/c Proton - Beryllium Interactions

Baltrusaitis, R.M. ; Binkley, Morris E. ; Cox, B. ; et al.
Phys.Rev.Lett. 44 (1980) 122, 1980.
Inspire Record 141769 DOI 10.17182/hepdata.42706

Measurements of recognized π0 production in p-Be collisions for 0.1

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

rivet Analysis
Study of Electron - Positron Collisions at the Highest {PETRA} Energy

The Aachen-DESY-Annecy(LAPP)-MIT-NIKHEF-Beijing collaboration Barber, D.P. ; Becker, U. ; Benda, H. ; et al.
Phys.Lett.B 85 (1979) 463-466, 1979.
Inspire Record 141976 DOI 10.17182/hepdata.27332

We report on the results of the study of e + e − collisions at the highest PETRA energy of √ s = 31.57 GeV, using the 4π sr, electromagnetic and calorimetric detector Mark J. Based on 88 hadron events, and an integrated luminosity of 243 nb −1 we obtain R = σ (e + e − → hadrons)/ σ (e + e − → μ + μ − ) = 4.0 ± 0.5 (statistical) ± 6 (systematic). The R value, the measured thrust distribution and average spherocity show no evidence for the production of new quark flavors.

2 data tables
Table 1

CORRECTIONS FOR TWO-PHOTON PROCESSES, TAU HEAVY LEPTON PRODUCTION AND INITIAL STATE RADIATIVE CORRECTIONS HAVE BEEN APPLIED.

Table 2

THRUST DISTRIBUTION (1/N)*DN/DTHRUST AT 31.57 GEV. THESE DATA ARE RATHER DETECTOR DEPENDENT.


Study of Electron - Positron Collisions at the Center-of-mass Energies of 27.4-{GeV} and 27.7-{GeV} at {PETRA}

Barber, D.P. ; Becker, U. ; Benda, H. ; et al.
Phys.Rev.Lett. 43 (1979) 901, 1979.
Inspire Record 141542 DOI 10.17182/hepdata.20739

This paper reports on the first results of the study of e+e− collisions at s=27.4 GeV and s=27.7 GeV at PETRA, using the 4π-sr electromagnetic and calorimetric detector MARK-J. We obtain an average R=σ(e+e−→hadrons)σ(e+e−→μ+μ−)=3.8±0.3 (statistical)±0.6 (systematic) and a relative R=1.0±0.2 between the two energies. The R values, the measured thrust distribution, and average spherocity show no evidence for the production of new quark flavors.

2 data tables
Table 1

THE RELATIVE VALUE OF R BETWEEN THESE TWO ENERGIES IS 1.0 +- 0.2.

Table 2

THRUST DISTRIBUTION (1/N)*DN/DTHRUST AT 13, 17 AND 27 GEV. THESE DATA ARE RATHER DETECTOR DEPENDENT.


A Search for Direct Photon Production in 200 GeV/c and 300 GeV/c Proton - Beryllium Interactions

Baltrusaitis, R.M. ; Binkley, Morris E. ; Cox, B. ; et al.
Phys.Lett.B 88 (1979) 372-378, 1979.
Inspire Record 142314 DOI 10.17182/hepdata.27292

A search has been made for direct photon production in pBe interactions at 200 and 300 GeV/ c over the kinematic region 1.5 < P ⊥ < 4.0 GeV/ c and −0.7 < X F < 0 (90° < θ cms < 160°). An excess of single photons above that which is predicted from the measured π 0 and η 0 production is observed. Theratio of γ / π 0 production is calculated assuming that the excess arises from direct photon production. We find that this ratio averages 0.070 ± 0.025 (including systematic errors) in this region of X F and P ⊥ for our 200 and 300 GeV/ c data. We have used our measured value of the η / π 0 ratio of 0.47 ± 0.10 in the determination of the γ / π 0 ratio. The variation of γ / π 0 with X F , P ⊥ , X R and θ cms presented.

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Discovery of Three Jet Events and a Test of Quantum Chromodynamics at PETRA Energies

Barber, D.P. ; Becker, U. ; Benda, H. ; et al.
Phys.Rev.Lett. 43 (1979) 830, 1979.
Inspire Record 142085 DOI 10.17182/hepdata.20742

We report the analysis of the spatial energy distribution of data for e+e−→hadrons obtained with the MARK-J detector at PETRA. We define the quantity "oblateness" to describe the flat shape of the energy configuration and the three-jet structure which is unambiguously observed for the first time. Our data can be explained by quantum chromodynamic predictions for the production of quark-antiquark pairs accompanied by hard noncollinear gluons.

1 data table
Table 1

AVERAGE OBLATENESS AS A FUNCTION OF SQRT(S) AND OF THRUST AND OBLATENESS DISTRIBUTION (1/N)*DN/DOBLATENESS AT 17 AND 27.4 TO 31.6 GEV. THESE DATA ARE RATHER DETECTOR DEPENDENT.


A Test of Universality of Charged Leptons

Barber, D.P. ; Becker, U. ; Benda, H. ; et al.
Phys.Rev.Lett. 43 (1979) 1915, 1979.
Inspire Record 142012 DOI 10.17182/hepdata.20759

Measurements of the reactions e++e−→e++e−, μ++μ−, and τ++τ− at PETRA energies (s12=13,17,27.4,30 and 31.6 GeV) are reported. The results show that these reactions agree well with the predictions of quantum electrodynamics thus determining that all the known charged leptons are pointlike particles to a distance < × 10−16 cm.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Tests of Quantum Chromodynamics and a Direct Measurement of the Strong Coupling Constant $\alpha_S$ at $\sqrt{s}=30$-{GeV}

Barber, D.P. ; Becker, U. ; Benda, H. ; et al.
Phys.Lett.B 89 (1979) 139-144, 1979.
Inspire Record 143680 DOI 10.17182/hepdata.6483

We report the measurement of the reaction e + + e − → hadronic jets at a center-of-mass energy √ s =30 GeV using the MARK-J detector at PETRA. By measuring the energy and angular distribution of both neutrals and charged particles we were able to isolate unambiguously the three-jet events in a kinematic region where the backgrounds from q q and phase space contributions and other processes are small. Various comparisons of the data with quantum chromodynamics were made. The relative yield of three-jet events and the shape distribution of the events enable us to determine α s = 0.23 ± 0.02 (statistical error) with a systematic error of ± 0.04.

2 data tables
Table 1

OBLATENESS AND THRUST DISTRIBUTIONS FOR NARROW AND BROAD JETS AT 30 GEV. THESE DATA ARE SOMEWHAT ANALYSIS AND DETECTOR DEPENDENT.

Table 2

No description provided.


Inclusive Production of $\pi^0$, $\K^0$(s), $\Lambda^0$, and Anti-lambda0 in 100-{GeV}/c, 200-{GeV}/c and 360-{GeV}/c $\pi^- p$ Interactions

Biswas, N.N. ; Higgins, P.D. ; Bishop, J.M. ; et al.
Nucl.Phys.B 167 (1980) 41-60, 1980.
Inspire Record 8802 DOI 10.17182/hepdata.34519

Inclusive cross sections for π 0 , K s 0 , Λ 0 and Λ 0 production in 100, 200 and 360 GeV /c π − p interactions are presented and compared with data at other energies. Invariant cross sections for γ, K s 0 , Λ 0 and Λ 0 production are presented in terms of Feynman x , the rapidity y , and transverse momentum squared, p T 2 . A comparison of the observed γ spectrum is made with the spectra computed assuming that the π 0 momentum distribution is identical to that of the observed π + or π − .

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…