Precision measurements of anti-proton proton forward elastic scattering parameters in the 3.7-GeV/c to 6.2-GeV/c region

The E760 collaboration Armstrong, T.A. ; Bettoni, D. ; Bharadwaj, V. ; et al.
Phys.Lett.B 385 (1996) 479-486, 1996.
Inspire Record 431921 DOI 10.17182/hepdata.28348

Differential cross sections for p p elastic scattering have been measured for very small momentum transfers at six different incident antiproton momenta in the range 3.7 to 6.2 GeV/c by the detection of recoil protons at scattering angles close to 90°. Forward scattering parameters σ T , b , and ϱ have been determined. For the ϱ-parameter, up to an order of magnitude higher level of precision has been achieved compared to that in earlier experiments. It is found that existing dispersion theory predictions are in disagreement with our results for the ϱ-parameter.

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Two-body neutral final states produced in $\bar{p}p$ annihilations at 2.911-GeV <= $\sqrt{s}$ <= 3.686-GeV

The Fermilab E760 collaboration Armstrong, T.A. ; Bettoni, D. ; Bharadwaj, V. ; et al.
Phys.Rev.D 56 (1997) 2509-2531, 1997.
Inspire Record 444897 DOI 10.17182/hepdata.22300

We have performed an experiment in the Antiproton Accumulator at Fermilab to study two-body neutral final states formed in p¯p annihilations. Differential cross sections are determined in the center-of-mass energy range 2.911<s<3.686 GeV for the final states π0π0, ηπ0, ηη, π0γ, and γγ. The energy dependence of differential cross sections at 90° in the center of mass is studied to test the predictions of phenomenological QCD scaling hypotheses which predict power-law dependence.

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Study of the eta(c) (s wave singlet) state of charmonium formed in anti-p p annihilations and a search for the eta(c)-prime (s wave doublet)

The E760 collaboration Armstrong, T.A. ; Bettoni, D. ; Bharadwaj, V. ; et al.
Phys.Rev.D 52 (1995) 4839-4854, 1995.
Inspire Record 395314 DOI 10.17182/hepdata.42381

The E760 Collaboration performed an experiment in the Antiproton Accumulator at Fermilab to study the two photon decay of the ηc(1 1S0) charmonium state formed in p¯p annihilations. This resulted in a new measurement of the mass Mηc=2988.3−3.1+3.3 MeV/c2 and of the product B(ηc→p¯p)×Γ(ηc→γγ) =(8.1−2.0+2.9) eV. We performed a search for the process p¯p→ηc′(2 1S0)→γγ over a limited range of center-of-mass energies. Since no signal was observed, we derived upper limits on the product of branching ratios B(ηc′→p¯p)×B(ηc′→γγ) in the center-of-mass energy range 3584≤ √s ≤3624 MeV. We observed no signal for the nonresonant process p¯+p→γ+γ and obtain upper limits.

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Inelastic and Elastic Photoproduction of J/$\psi$ (3097)

Denby, Bruce H. ; Bharadwaj, V.K. ; Summers, D.J. ; et al.
Phys.Rev.Lett. 52 (1984) 795-798, 1984.
Inspire Record 195929 DOI 10.17182/hepdata.20438

Inelastic and elastic $J/\psi$ photoproduction on hydrogen are investigated at a mean energy of 105 GeV. The inelastic cross section with $E_{\psi} / E_{\gamma}$ < 0.9 is significantly lower than the corresponding result for muoproduction on iron targets, but is consistent with a second-order perturbative QCD calculation.

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A Study of D* Production in High-Energy $\gamma$ p Interactions

Sliwa, K. ; Appel, J.A. ; Biel, J. ; et al.
Phys.Rev.D 32 (1985) 1053-1060, 1985.
Inspire Record 194636 DOI 10.17182/hepdata.23561

We have studied D* production mechanisms using data from a photoproduction experiment at the Fermilab Tagged Photon Spectrometer. A large sample of charged D*’s was selected via the clean signature of the cascade decay D*→D0π+ and subsequently D0→K−π+ or D0→K−π+π0. The cross section for the process γp→(D*++anything)p at an average energy of 105 GeV was measured to be 88±32 nb. Only (11±7)% of D*’s were found to be consistent with being accompanied solely by a D¯* or a D¯; the remaining events contain additional particles. The distribution of the production angle of the D* in the photon-fragmentation-system center of mass is strongly anisotropic and consistent with the form f(θ*)=cos4θ*. We set a limit on the associated-production-process cross section σ(γp→(D¯*−+anything)Λc) x)<60 nb (90% C.L.).

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Multiplicity of Charged Particles in 800-{GeV} $p p$ Interactions

The LEBC-MPS collaboration Ammar, R. ; Aziz, T. ; Banerjee, S. ; et al.
Phys.Lett.B 178 (1986) 124-128, 1986.
Inspire Record 231133 DOI 10.17182/hepdata.6558

Results are reported concerning the charged-particle multiplicity distribution obtained in an exposure of the high-resolution hydrogen bubble chamber LEBC to a beam of 800 GeV protons at the Fermilab MPS. This is the first time that such data have been available at this energy. The distribution of the number n ch of charged particles produced in inelastic interactions obeys KNO-scaling. The average multiplicity is 〈 n ch 〉 = 10.26±0.15. For n ch ⩾8 the data can be well fitted to a negative binomial. The difference between the overall experimental multiplicity distribution and that resulting from the latter fit is in agreement with the contribution expected from diffractive processes.

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The Production of J/psi and Associated Particles in the Collision of 530-GeV/c Protons and Pions with Nuclear Targets

De, K. ; Crittenden, R. ; Dzierba, A. ; et al.
(1989) 467-472, 1989.
Inspire Record 280605 DOI 10.17182/hepdata.22998
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$K_s^0$ production in $\bar{p}p$ interactions at $\sqrt{s}=$ 630 GeV and 1800 GeV

The CDF collaboration Abe, F. ; Amidei, D. ; Apollinari, G. ; et al.
Phys.Rev.D 40 (1989) 3791-3794, 1989.
Inspire Record 287811 DOI 10.17182/hepdata.22999

Measurements of inclusive transverse-momentum spectra for KS0 mesons produced in proton-antiproton collisions at s of 630 and 1800 GeV are presented and compared with data taken at lower energies. The ratio, as a function of pT, of the cross section for KS0 to that for charged hadrons is very similar to what is observed at lower energies. At 1800 GeV, we calculate the strangeness-suppression factor λ=0.40±0.05.

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Multiparticle Production by 200-GeV/c Hadrons on Gold, Silver, and Magnesium Targets

Brick, D.H. ; Widgoff, M. ; Beilliere, P. ; et al.
Phys.Rev.D 39 (1989) 2484-2493, 1989.
Inspire Record 282254 DOI 10.17182/hepdata.23227

We have used the Fermilab 30-in. bubble-chamber hybrid spectrometer to study multiparticle production in the interactions of 200-GeV/c protons and π+ and K+ mesons with nuclei of gold, silver, and magnesium. We find that the multiplicities of produced particles and negative particles increase linearly with the number of projectile collisions, with no beam or target dependence. The number of secondary collisions in the nucleus increases significantly less rapidly with the number of projectile collisions than has been reported by a streamer chamber experiment. The properties of secondary collisions suggest that they arise from rescattering of recoil nucleons rather than intranuclear cascade of produced particles. Dispersions of multiplicity distributions at fixed impact parameter are in better agreement with a model of independent sources than with Koba-Nielsen-Olesen scaling.

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Total cross-section measurements with pi-, Sigma- and protons on nuclei and nucleons around 600-GeV/c

The SELEX collaboration Dersch, U. ; Akchurin, N. ; Andreev, V.A. ; et al.
Nucl.Phys.B 579 (2000) 277-312, 2000.
Inspire Record 509036 DOI 10.17182/hepdata.24823

Total cross sections for Sigma- and pi- on beryllium, carbon, polyethylene and copper as well as total cross sections for protons on beryllium and carbon have been measured in a broad momentum range around 600GeV/c. These measurements were performed with a transmission technique adapted to the SELEX hyperon-beam experiment at Fermilab. We report on results obtained for hadron-nucleus cross sections and on results for sigma_tot(Sigma- N) and sigma_tot(pi- N), which were deduced from nuclear cross sections.

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Distributions of charged hadrons observed in deep inelastic muon - deuterium scattering at 490-GeV

The E-665 collaboration Adams, M.R. ; Aid, S. ; Anthony, P.L. ; et al.
Phys.Lett.B 272 (1991) 163-168, 1991.
Inspire Record 318993 DOI 10.17182/hepdata.29288

Longitudinal and transverse momentum spectra of final state hadrons produced in deep-inelastic muon-deuterium scattering at incident muon energy of 490 GeV have been measured up to a hadronic center of mass energy of 30 GeV. The longitudinal distributions agree well with data from earlier muon-nucleon scattering experiments; these distributions tend to increase in steepness as the center of mass energy increases. Comparisons with e + e − data at comparable center of mass energies indicate slight differences. The transverse momentum distributions show an increase in mean p T 2 with an increase in the center of mass energy.

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Production of Jets and Single Particles at High p(T) in 200-GeV Hadron Beryllium Collisions

Bromberg, C. ; Fox, G. ; Gomez, R. ; et al.
Nucl.Phys.B 134 (1978) 189-241, 1978.
Inspire Record 5774 DOI 10.17182/hepdata.35152

We present results from an experiment studying the production of single particles and jets (groups of particles) with high p ⊥ (transverse momentum) in 200 GeV/ c interactions on a beryllium target. We give a detailed discussion of the ambiguities in the jet definition. The jet and single-particle cross sections have a similar shape but the jet cross section is over two orders of magnitude larger. The events show evidence for the coplanar structure suggested by constituent models, and the momentum distributions of charged particles give strong support to a simple quark-quark scattering model.

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Inelastic Two Prong Events in 147-GeV/c pi- p Collisions.

Fong, D. ; Heller, M. ; Shapiro, A. ; et al.
Nucl.Phys.B 104 (1976) 32-51, 1976.
Inspire Record 112609 DOI 10.17182/hepdata.36026
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Cross-Sections and Charged Multiplicity Distributions for pi- p and K- p Interactions at 147-GeV/c.

Fong, D. ; Heller, M. ; Shapiro, A.M. ; et al.
Nucl.Phys.B 102 (1976) 386-404, 1976.
Inspire Record 112604 DOI 10.17182/hepdata.36057

The results presented in this paper were obtained from a 105 000 frame exposure of the FNAL Hybrid Proportional Wire Chamber-30 inch Bubble Chamber System, in a tagged beam of 147 GeV/ c negative particles. Elastic, total and topological cross sections were obtained for both π − p and K − p interactions. Comparisons with other data, taken with various beam particles over large momentum intervals, show good agreement with KNO scaling, and similarity in the scaling behavior of σ n for the different beam particles.

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Real Part of the Proton Proton Forward Scattering Amplitude from 50 GeV to 400 GeV.

Bartenev, V. ; Carrigan, Richard A. ; Chiang, I-Hung ; et al.
Phys.Rev.Lett. 31 (1973) 1367-1370, 1973.
Inspire Record 81733 DOI 10.17182/hepdata.21379

From measurements of proton-proton elastic scattering at very small momentum transfers where the nuclear and Coulomb amplitudes interfere, we have deduced values of ρ, the ratio of the real to the imaginary forward nuclear amplitude, for energies from 50 to 400 GeV. We find that ρ increases from -0.157 ± 0.012 at 51.5 GeV to +0.039 ± 0.012 at 393 GeV, crossing zero at 280 ± 60 GeV.

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Measurement of the Slope of the Diffraction Peak for Elastic pp Scattering from 8-GeV to 400-GeV.

Bartenev, V. ; Kuznetsov, A. ; Morozov, B. ; et al.
Phys.Rev.Lett. 31 (1973) 1088-1091, 1973.
Inspire Record 81722 DOI 10.17182/hepdata.21381

The slope b(s) of the forward diffraction peak of p−p elastic scattering has been measured in the momentum-transfer-squared range 0.005≲|t|≲0.09 (GeV/c)2 and at incident proton energies from 8 to 400 GeV. We find that b(s) increases with s, and in the interval 100≲s≲750 (GeV)2 it can be fitted by the form b(s)=b0+2α′lns with b0=8.23±0.27, α′=0.278±0.024 (GeV/c)−2.

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Small Angle Elastic Proton Proton Scattering from 25-GeV to 200-GeV.

Bartenev, V. ; Kuznetsov, A. ; Morozov, B. ; et al.
Phys.Rev.Lett. 29 (1972) 1755-1758, 1972.
Inspire Record 73778 DOI 10.17182/hepdata.21428

We have measured the differential cross section for small angle p−p scattering from 25 to 200 GeV incident energy and in the momentum transfer range 0.015<|t|<0.080 (GeVc)2. We find that the slope of the forward diffraction peak, b(s), increases with energy and can be fitted by the form b(s)=b0+2α′ lns, where b0=8.3±1.3 and α′=0.28±0.13 (GeVc)−2. Such dependence is compatible with the data existing both at higher and lower energies. We have also obtained the energy dependence of the p−p total cross section in the energy range from 48 to 196 GeV. Within our errors which are ± 1.1 mb the total cross section remains constant.

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Sigma- p, xi- p, and pi- p Elastic Scattering at 23-GeV/c

Majka, R. ; Hungerbuhler, V. ; Marx, J.N. ; et al.
Phys.Rev.Lett. 37 (1976) 413-416, 1976.
Inspire Record 114489 DOI 10.17182/hepdata.21070

We present results from a measurement of the differential cross sections for Σ−p, Ξ−p, and π−p elastic scattering at 23 GeV/c. We have collected samples of 6200 Σ−p events, 67 Ξ−p events, and 30 000 π−p events in the interval 0.10<|t|<0.23 (GeV/c)2.

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$\Sigma^{-}$ production in high-energy proton interactions

Hungerbuehler, V. ; Majka, R. ; Marx, J.N. ; et al.
Phys.Rev.Lett. 30 (1973) 1234-1237, 1973.
Inspire Record 84497 DOI 10.17182/hepdata.21625

Momentum spectra for forward Σ− production on beryllium by protons of momentum 25.8 and 29.4 GeVc are presented. Data for the two primary proton momenta are compared for scaling behavior in the invariant cross section. In addition, the observed single-particle momentum distributions are compared with single-particle spectra from other inclusive reactions initiated by protons.

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A Measurement of High $P_T$ Correlations in 340-GeV/c pp and 280-GeV/c $\pi^- p$ Reactions

Oliver, W.P. ; Limon, P. ; Mantsch, Paul M. ; et al.
Nucl.Phys.B 228 (1983) 439-463, 1983.
Inspire Record 189533 DOI 10.17182/hepdata.33923

We have measured correlations between single high- p T (1.5< p T <3.5 GeV/ c ) trigger particles on one side of the beam line and groups of particles entering a calorimeter on the opposite side of the beam line. The mean transverse momentum measured in the calorimeter is found to increase with the trigger-particle transverse momentum. The coplanarity of the events increases with trigger-particle transverse momentum. We have compared our data with the predictions of a phenomenological four-jet model. To fit our data we find that we must give large (0.9 GeV/ c ) mean transverse momenta to the constituents of the initial hadrons.

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The Exclusive Channel pi- pi- pi+ p in pi- p Interactions at 147-GeV/c.

Fong, D. ; Heller, M. ; Shapiro, A.M. ; et al.
Nuovo Cim.A 34 (1976) 659-671, 1976.
Inspire Record 112629 DOI 10.17182/hepdata.37618

The results of a study of the reaction π-p→π-π-π+p at2 147 GeV/c carried out at the Fermilab Proportional Wire 30″ Bubble Chamber Hybrid Spectrometer are reported. More than 92% of the cross-section ((670±41) μb) for this reaction is contained in those for proton and pion diffraction dissociation. The cross-sections for pion diffraction events with three-pion invariant mass in given regions are in agreement with values obtained by extrapolation of fits to data at lower incidentpion momenta. ρ0π- events make an important contribution in the A1 and A2 mass regions, and the data are consistent with contributions from f0π- in the A3 mass region. The cross-section for proton diffraction events is in agreement with a smooth extrapolation of the data at lower momentum.

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Brick, D.H. ; Rudnicka, H. ; Shapiro, A.M. ; et al.
Nucl.Phys.B 201 (1982) 189-196, 1982.
Inspire Record 181081 DOI 10.17182/hepdata.34199

We report on the interactions of an incident 200 GeV / c beam composed of 33% protons, 16% kaons, and 48% pions on targets of silver and gold mounted in the Fermilab 30″ bubble chamber. Within our limited statistics, we find the total cross sections and average multiplicities to agree with previously published data. We find the KNO scaling distribution curve to be broader for heavy nuclei than for hydrogen. We present the first data for V 0 production on gold and silver. We also present, for the first time, evidence for a positive charge excess among the sample of relativistic tracks from interactions on gold and silver. We observe a trend where the positive charge excess increases with target atomic number and with increasing charged particle multiplicity. We find the charge excess to exist among the sample of particles having greater than 2 GeV / c momentum and to persist in the sample with momentum greater than 4 GeV / c .

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Model-independent measurement of the $W$ boson helicity in top quark decays at D0

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 100 (2008) 062004, 2008.
Inspire Record 767094 DOI 10.17182/hepdata.47072

We present the first model-independent measurement of the helicity of $W$ bosons produced in top quark decays, based on a 1 fb$^{-1}$ sample of candidate $t\bar{t}$ events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron $p\bar{p}$ Collider. We reconstruct the angle $\theta^*$ between the momenta of the down-type fermion and the top quark in the $W$ boson rest frame for each top quark decay. A fit of the resulting \costheta distribution finds that the fraction of longitudinal $W$ bosons $f_0 = 0.425 \pm 0.166 \hbox{(stat.)} \pm 0.102 \hbox{(syst.)}$ and the fraction of right-handed $W$ bosons $f_+ = 0.119 \pm 0.090 \hbox{(stat.)} \pm 0.053 \hbox{(syst.)}$, which is consistent at the 30% C.L. with the standard model.

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Measurement of the $\sigma(W + \ge 1 {\rm jet})/\sigma(W)$ cross section ratio from $\bar{p}p$ collisions at $\sqrt{s} = 1.8$ TeV

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 81 (1998) 1367-1372, 1998.
Inspire Record 469969 DOI 10.17182/hepdata.42146

The ratio of the W+≥1 jet cross section to the inclusive W cross section is measured using W±→e±ν events from p¯p collisions at s=1.8TeV. The data are from 108pb−1 of integrated luminosity collected with the Collider Detector at Fermilab. Measurements of the cross section ratio for jet transverse energy thresholds (ETmin) ranging from 15 to 95 GeV are compared to theoretical predictions using next-to-leading-order QCD calculations. Data and theory agree well for ETmin>25GeV, where the predictions lie within 1 standard deviation of the measured values.

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Charged Jet Evolution and the Underlying Event in $p\bar{p}$ Collisions at 1.8 TeV

The CDF collaboration Affolder, T. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.D 65 (2002) 092002, 2002.
Inspire Record 564673 DOI 10.17182/hepdata.42044

The growth and development of “charged particle jets” produced in proton-antiproton collisions at 1.8 TeV  are studied over a transverse momentum range from 0.5 GeV/c to 50 GeV/c. A variety of leading (highest transverse momentum) charged jet observables are compared with the QCD Monte Carlo models HERWIG, ISAJET, and PYTHIA. The models describe fairly well the multiplicity distribution of charged particles within the leading charged jet, the size of the leading charged jet, the radial distribution of charged particles and transverse momentum around the leading charged jet direction, and the momentum distribution of charged particles within the leading charged jet. The direction of the leading “charged particle jet” in each event is used to define three regions of η−φ space. The “toward” region contains the leading “charged particle jet,” while the “away” region, on the average, contains the away-side jet. The “transverse” region is perpendicular to the plane of the hard 2-to-2 scattering and is very sensitive to the “underlying event” component of the QCD Monte Carlo models. HERWIG, ISAJET, and PYTHIA with their default parameters do not describe correctly all the properties of the “transverse” region.

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