Jakobs, Karl
UA2
hep-ex
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Direct Photon Production in $\bar{p} p$ Collisions at $\sqrt{s}=630$-{GeV}

The UA2 collaboration Ansari, R. ; Bagnaia, P. ; Banner, M. ; et al.
Z.Phys.C 41 (1988) 395, 1988.
Inspire Record 264998 DOI 10.17182/hepdata.15558

A measurement of the direct production of photons with high transverse momentum from\(\bar pp\) collisions at\(\sqrt s= 630\) GeV is presented. The structure of events containing a high transverse momentum photon is studied. The results support predictions from QCD theory.

5 data tables match query
Table 1

The last data point is an average over the interval 60-100 GeV in which 5 events are found.

Table 2

No description provided.

Table 3

No description provided.

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A Determination of the strong coupling constant alpha-s from W production at the CERN p anti-p collider

The UA2 collaboration Alitti, J. ; Ambrosini, G. ; Ansari, R. ; et al.
Phys.Lett.B 263 (1991) 563-572, 1991.
Inspire Record 315374 DOI 10.17182/hepdata.29394

The large sample of W→eν events collected by the UA2 experiment at the CERN pp̄ collider between 1988 and 1990 has been used to determine the strong coupling constant α s . From a measurement of the ratio of the production rate of W events with one jet to that with no jets, α s has been extracted to second order in the MS ̄ scheme: α s (M 2 w )=0.123±0.0.18( stat .)±0.017 ( syst .) .

1 data table match query
Table 1

ALP_S extracted to second order in the MSbar scheme.


A Study of Three Jet Events at the {CERN} $\bar{p} p$ Collider

The UA2 collaboration Appel, J.A. ; Bagnaia, P. ; Banner, M. ; et al.
Z.Phys.C 30 (1986) 341, 1986.
Inspire Record 219453 DOI 10.17182/hepdata.15897

The UA2 experiment, running at the CERN SPS\(\bar pp\) Collider, has performed a study of events containing three hard jets in the final state. The angular distributions of the three jets show evidence for gluon bremsstrahlung, in good agreement with a QCD model to leading order in the strong coupling constant αs. The yield of three-jet events relative to that of two-jet events provides a measure of the strong coupling constant: ;3K3/K2=0.23±0.01±0.04, whereK2 andK3 represent the contributions arising from higher order corrections in α3 to the two- and three-jet exclusive cross-sections. A detailed discussion of the systematic and theoretical uncertainties is given.

1 data table match query
Table 1

No description provided.


Direct Photon Production at the {CERN} $\bar{p} p$ Collider

The UA2 collaboration Appel, J.A. ; Bagnaia, P. ; Banner, M. ; et al.
Phys.Lett.B 176 (1986) 239, 1986.
Inspire Record 229895 DOI 10.17182/hepdata.30247

Using the UA2 apparatus, the inclusive cross section has been measured for production of high- p T direct photons in p̄p collisions at s =546 GeV and s =630 GeV . The results are in good agreement with QCD predictions.

2 data tables match query
Table 1

No description provided.

Table 2

No description provided.


A Study of multi - jet events at the CERN anti-p p collider and a search for double parton scattering

The UA2 collaboration Alitti, J. ; Ambrosini, G. ; Ansari, R. ; et al.
Phys.Lett.B 268 (1991) 145-154, 1991.
Inspire Record 317817 DOI 10.17182/hepdata.29361

A study of events containing at least four high transverse momentum jets and a search for double parton scattering (DPS) have been performed using data collected with the UA2 detector at the CERN p p Collider (√ s =630 GeV). The results are in good agreement with leading order QCD calculations. A value of σ DPS <0.82 nb at 95% confidence level (CL) is obtained for the DPS cross section.

2 data tables match query
Table 2

Uncorrected cross sections.

Table 3

Upper limit to DPS contribution to 4JET production.


Measurement of W and Z Production Cross-sections at the CERN $\bar{p}p$ Collider

The UA2 collaboration Alitti, J. ; Ansari, R. ; Ansorge, R.E. ; et al.
Z.Phys.C 47 (1990) 11-22, 1990.
Inspire Record 294910 DOI 10.17182/hepdata.15179

Results on the production cross sections ofW andZ bosons detected in the UA2 experiment are given based on a large sample ofW→eν andZ→e+e− decays. The measured cross sections are σWe = 660±15(stat)±37(syst)pb, σZe = 70.4±5.5(stat)±4.0(syst)pb and their ratioR=9.38−0.72+0.82(stat)±0.25(syst). In the framework of the Standard Model, the measured value ofR is used to determine the total width of theW, Γ(W)=2.30±0.19(stat)±0.06(syst) GeV.

3 data tables match query
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Measurement of the Transverse Momentum Distributions of $W$ and $Z$ Bosons at the {CERN} $\bar{p} p$ Collider

The UA2 collaboration Alitti, J. ; Ansari, R. ; Ansorge, R.E. ; et al.
Z.Phys.C 47 (1990) 523-532, 1990.
Inspire Record 296184 DOI 10.17182/hepdata.15150

The transverse momentum distributions ofW andZ bosons produced in\(\bar pp\) collisions at\(\sqrt s= 630 GeV\) are examined. Comparisons are made with QCD predictions, and good agreement is found. The fraction ofW bosons produced withpT>25 GeV is found to be 3.8±0.6(stat)−1.3+0.9(syst)%.

2 data tables match query
Table 1

No description provided.

Table 2

Combining the cross section for pbar p --> W X * BR(W --> E NU) given in Alitti et al, ZP C47 (90) 11. (660 +- 15 (DSYS=37) pb).


Study of electron pair production below the Z mass at the CERN anti-p p collider

The UA2 collaboration Alitti, J. ; Ambrosini, G. ; Ansari, R. ; et al.
Phys.Lett.B 275 (1992) 202-208, 1992.
Inspire Record 322265 DOI 10.17182/hepdata.27115

Results on the cross section for the production of electron pairs in p p collisions at √ s = 630 GeV are presented. The measured value is σ = 405 ± 51 (syst.) ± 84 (syst.) pb, in the invariant mass interval 10 < m < 70 GeV. The results are compared to recent theoretical calculations which include O( α s 2 ) QCD contributions. The comparison of these data with those of lower energy experiments show approximate scaling as a function of the variable √τ = m √s .

3 data tables match query
Table 1

No description provided.

Table 2

Statistical and systematic errors combined.

Table 3

Statistical errors only.


A Measurement of the direct photon production cross-section at the CERN anti-p p collider

The UA2 collaboration Alitti, J. ; Ambrosini, G. ; Ansari, R. ; et al.
Phys.Lett.B 263 (1991) 544-550, 1991.
Inspire Record 315377 DOI 10.17182/hepdata.47328

A measurement of the inclusive cross-section for production of direct photons in p̄p collisions at a centre of mass energy of 630 GeV is presented as a function of the photon transverse momentum. The data correspond to a total integrated luminosity of 7.4 pb −1 . The results support predictions from QCD theory.

1 data table match query
Table 1

No description provided.


Measurement of W+- and Z0 Properties at the CERN anti-p p Collider

The UA2 collaboration Appel, J.A. ; Bagnaia, P. ; Banner, M. ; et al.
Z.Phys.C 30 (1986) 1, 1986.
Inspire Record 218462 DOI 10.17182/hepdata.2113

A study ofW± andZ0 properties has been performed using the UA2 detector at the\(\bar pp\) collider. The data correspond to a total integrated luminosity of 142 nb−1 at\(\sqrt s \)=546 GeV, and of 310 nb−1 at\(\sqrt s \)=630 GeV. The experimental results are compared with the predictions of the Standard Model of the unified electroweak theory.

3 data tables match query
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.