Date

Single-Pion Production in pp Collisions at 0.95 GeV/c (II)

The COSY-TOF collaboration Abd El-Samad, S. ; Bilger, R. ; Brinkmann, K.-Th. ; et al.
Eur.Phys.J.A 39 (2009) 281-289, 2009.
Inspire Record 790164 DOI 10.17182/hepdata.50496

The single-pion production reactions $pp\to d\pi^+$, $pp\to np\pi^+$ and $pp\to pp\pi^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p \approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements from other detector parts. Thus all pion production channels were recorded with 1-4 overconstraints. Main emphasis is put on the presentation and discussion of the $np\pi^+$ channel, since the results on the other channels have already been published previously. The total and differential cross sections obtained are compared to theoretical calculations. In contrast to the $pp\pi^0$ channel we find in the $np\pi^+$ channel a strong influence of the $\Delta$ excitation already at this energy close to threshold. In particular we find a $(3 cos^2\Theta + 1)$ dependence in the pion angular distribution, typical for a pure s-channel $\Delta$ excitation and identical to that observed in the $d\pi^+$ channel. Since the latter is understood by a s-channel resonance in the $^1D_2$ $pn$ partial wave, we discuss an analogous scenario for the $pn\pi^+$ channel.

6 data tables

Differential cross section for the process P P --> P N PI+ as a function ofthe P PI+ mass.

Differential cross section for the process P P --> P N PI+ as a function ofthe N PI+ mass.

Differential cross section for the process P P --> P N PI+ as a function ofthe P N mass.

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Measurement of the cross section for prompt diphoton production in p anti-p collisions at s**(1/2) = 1.96-TeV

The CDF collaboration Acosta, D. ; Adelman, J. ; Affolder, T. ; et al.
Phys.Rev.Lett. 95 (2005) 022003, 2005.
Inspire Record 667384 DOI 10.17182/hepdata.41865

We report a measurement of the rate of prompt diphoton production in $p\bar{p}$ collisions at $\sqrt{s}=1.96 ~\hbox{TeV}$ using a data sample of 207 pb$^{-1}$ collected with the upgraded Collider Detector at Fermilab (CDF II). The background from non-prompt sources is determined using a statistical method based on differences in the electromagnetic showers. The cross section is measured as a function of the diphoton mass, the transverse momentum of the diphoton system, and the azimuthal angle between the two photons and is found to be consistent with perturbative QCD predictions.

3 data tables

Cross section as a function of the diphoton mass.

Cross section as a function of the diphoton transverse momentum.

Cross section as a function of the diphoton azimuthal angle difference.


Measurement of dijet azimuthal decorrelations at central rapidities in p anti-p collisions at s**(1/2) = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 94 (2005) 221801, 2005.
Inspire Record 659398 DOI 10.17182/hepdata.19397

Correlations in the azimuthal angle between the two largest transverse momentum jets have been measured using the D0 detector in pp-bar collisions at a center-of-mass energy sqrt(s)=1.96 TeV. The analysis is based on an inclusive dijet event sample in the central rapidity region corresponding to an integrated luminosity of 150 pb-1. Azimuthal correlations are stronger at larger transverse momenta. These are well-described in perturbative QCD at next-to-leading order in the strong coupling constant, except at large azimuthal differences where soft effects are significant.

4 data tables

Distribution for the maxPT jet from 75 to 100 GeV.

Distribution for the maxPT jet from 100 to 130 GeV.

Distribution for the maxPT jet from 130 to 180 GeV.

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The b anti-b production cross-section and angular correlations in p anti-p collisions at S**(1/2) = 1.8-TeV

The D0 collaboration Abbott, B. ; Abolins, M. ; Abramov, V. ; et al.
Phys.Lett.B 487 (2000) 264-272, 2000.
Inspire Record 499943 DOI 10.17182/hepdata.42088

We present measurements of the b-bbar production cross section and angular correlations using the D0 detector at the Fermilab Tevatron p-pbar Collider operating at sqrt(s) = 1.8 TeV. The b quark production cross section for |y(b)|<1.0 and p_T(b)>6 GeV/c is extracted from single muon and dimuon data samples. The results agree in shape with the next-to-leading order QCD calculation of heavy flavor production but are greater than the central values of these predictions. The angular correlations between b and bbar quarks, measured from the azimuthal opening angle between their decay muons, also agree in shape with the next-to-leading order QCD prediction.

3 data tables

No description provided.

The errors are combinations of statistical and systematic uncertainties.

The distribution of MU+ MU- azimuthal angle difference.


The Azimuthal decorrelation of jets widely separated in rapidity

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 77 (1996) 595-600, 1996.
Inspire Record 416886 DOI 10.17182/hepdata.42315

This study reports the first measurement of the azimuthal decorrelation between jets with pseudorapidity separation up to five units. The data were accumulated using the D\O\ detector during the 1992--1993 collider run of the Fermilab Tevatron at $\sqrt{s}=$ 1.8 TeV. These results are compared to next--to--leading order (NLO) QCD predictions and to two leading--log approximations (LLA) where the leading--log terms are resummed to all orders in $\alpha_{\scriptscriptstyle S}$. The final state jets as predicted by NLO QCD show less azimuthal decorrelation than the data. The parton showering LLA Monte Carlo {\small HERWIG} describes the data well; an analytical LLA prediction based on BFKL resummation shows more decorrelation than the data.

3 data tables

Distribution of the pseudorapidity interval of the two jets at the extremes of pseudorapidity. Data are read from the graph and the errors are statistical only.

Normalized distributions of the azimuthal angle difference of the two jets at the extremes of pseudorapidity in 3 pseudorapididity difference intervals. Data are read from the graph and the errors are statistical only.

The correlation between the PHI and ETARAP difference distributions as used in the analysis.Data are read from the graph and the errors include the statiucal and un-correlated systematic errors added in quadrature.


Measurement of the cross-section for production of two isolated prompt photons in anti-p p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Albrow, Michael G. ; Amidei, Dante E. ; et al.
Phys.Rev.Lett. 70 (1993) 2232-2236, 1993.
Inspire Record 343802 DOI 10.17182/hepdata.19755

We present measurements from events with two isolated prompt photons in p¯p collisions at √s =1.8 TeV. The differential cross section, measured as a function of transverse momentum (PT) of each photon, is about 3 times what next-to-leading-order QCD calculations predict. The cross section for photons with PT in the range 10–19 GeV is 86±27(stat)−23+32(syst) pb. We also study the correlation between the two photons in both azimuthal angle and PT. The magnitude of the vector sum of the transverse momenta of both photons, KT=‖PT1+PT2‖, has a mean value of 〈KT〉=5.1±1.1 GeV.

5 data tables

No description provided.

No description provided.

Vector sum of the photons transvserse momenta.. Errors contain both statistics and systematics.. Data read from plots.

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psi production and anti-p N and pi- N interactions at 125-GeV/c and a determination of the gluon structure functions of the anti-p and the pi-

Tzamarias, S. ; Katsanevas, S. ; Kourkoumelis, C. ; et al.
Phys.Rev.D 48 (1993) 5067-5080, 1993.
Inspire Record 297586 DOI 10.17182/hepdata.22578

We have measured the cross section for production of ψ and ψ′ in p¯ and π− interactions with Be, Cu, and W targets in experiment E537 at Fermilab. The measurements were performed at 125 GeV/c using a forward dimuon spectrometer in a closed geometry configuration. The gluon structure functions of the p¯ and π− have been extracted from the measured dσdxF spectra of the produced ψ's. From the p¯W data we obtain, for p¯, xG(x)=(2.15±0.7)[1−x](6.83±0.5)[1+(5.85±0.95)x]. In the π− case, we obtain, from the W and the Be data separately, xG(x)=(1.49±0.03)[1−x](1.98±0.06) (for π−W), xG(x)=(1.10±0.10)[1−x](1.20±0.20) (for π−Be).

24 data tables

No description provided.

No description provided.

No description provided.

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Comparison of the Particle Flow in $q \bar{q} \gamma$ and $q \bar{q} g$ Events From $e^+ e^-$ Annihilations at {PETRA}

The JADE collaboration Saada, F.Ould ; Allison, J. ; Ambrus, K. ; et al.
Z.Phys.C 39 (1988) 1, 1988.
Inspire Record 260834 DOI 10.17182/hepdata.15623

The particle flow distributions in the event plane of 3-jet\((e^ +e^ -\to q\bar qg)\) and of radiative 2-jet\((e^ +e^ -\to q\bar q\gamma )\) events are compared at a centre of mass energy of 35 GeV. The number of particles in the angular region opposite to the gluon in\(q\bar qg\) events is found to be significantly reduced relative to the number of particles in the region opposite to the hard photon in\(q\bar q\gamma \) events. This depletion is expected from the “string effect” observed in 3-jet events. It can be explained within the framework of QCD as arising from soft gluon interference.

1 data table

Data requested from authors.


TESTS OF MODELS FOR PARTON FRAGMENTATION USING THREE JET EVENTS IN e+ e- ANNIHILATION the s**(1/2) = 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Bakken, J.A. ; et al.
Phys.Rev.Lett. 54 (1985) 270, 1985.
Inspire Record 205871 DOI 10.17182/hepdata.20358

The distribution of particles in three-jet events is compared with the predictions of three fragmentation models currently in use: the Lund string model, the Webber cluster model, and an independent fragmentation model. The Lund model and, to a certain extent, the Webber model provide reasonable descriptions of the data. The independent fragmentation model does not describe the distribution of particles at large angles with respect to the jet axes. The results provide evidence that the sources of hadrons are Lorentz boosted with respect to the overall c.m.

1 data table

No description provided.