Kaon Pair Production in Proton--Proton Collisions

The ANKE collaboration Maeda, Y. ; Hartmann, M. ; Keshelashvili, I. ; et al.
Phys.Rev.C 77 (2008) 015204, 2008.
Inspire Record 763646 DOI 10.17182/hepdata.25173

The differential and total cross sections for kaon pair production in the pp->ppK+K- reaction have been measured at three beam energies of 2.65, 2.70, and 2.83 GeV using the ANKE magnetic spectrometer at the COSY-Juelich accelerator. These near-threshold data are separated into pairs arising from the decay of the phi-meson and the remainder. For the non-phi selection, the ratio of the differential cross sections in terms of the K-p and K+p invariant masses is strongly peaked towards low masses. This effect can be described quantitatively by using a simple ansatz for the K-p final state interaction, where it is seen that the data are sensitive to the magnitude of an effective K-p scattering length. When allowance is made for a small number of phi events where the K- rescatters from the proton, the phi region is equally well described at all three energies. A very similar phenomenon is discovered in the ratio of the cross sections as functions of the K-pp and K+pp invariant masses and the identical final state interaction model is also very successful here. The world data on the energy dependence of the non-phi total cross section is also reproduced, except possibly for the results closest to threshold.

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Version 2
Dihadron azimuthal correlations in Au$+$Au collisions at $\sqrt{s_{NN}}=$ 200 GeV

The PHENIX collaboration Adare, A. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 78 (2008) 014901, 2008.
Inspire Record 778396 DOI 10.17182/hepdata.96764

Azimuthal angle (Delta phi) correlations are presented for a broad range of transverse momentum (0.4 < pT < 10 GeV/c) and centrality (0-92%) selections for charged hadrons from di-jets in Au+Au collisions at sqrt(s_NN) = 200 GeV. With increasing pT, the away-side Delta phi distribution evolves from a broad and relatively flat shape to a concave shape, then to a convex shape. Comparisons to p+p data suggest that the away-side distribution can be divided into a partially suppressed head region centered at Delta phi ~ \pi, and an enhanced shoulder region centered at Delta phi ~ \pi \pm 1:1. The pT spectrum for the associated hadrons in the head region softens toward central collisions. The spectral slope for the shoulder region is independent of centrality and trigger pT . The properties of the near-side distributions are also modified relative to those in p + p collisions, reflected by the broadening of the jet shape in Delta phi and Delta eta, and an enhancement of the per-trigger yield. However, these modifications seem to be limited to pT < 4 GeV/c, above which both the dihadron pair shape and per-trigger yield become similar to p + p collisions. These observations suggest that both the away- and near-side distributions contain a jet fragmentation component which dominates for pT \ge 5GeV and a medium-induced component which is important for pT \le 4 GeV/c. We also quantify the role of jets at intermediate and low pT through the yield of jet-induced pairs in comparison to binary scaled p + p pair yield. The yield of jet-induced pairs is suppressed at high pair proxy energy (sum of the pT magnitudes of the two hadrons) and is enhanced at low pair proxy energy. The former is consistent with jet quenching/ the latter is consistent with the enhancement of soft hadron pairs due to transport of lost energy to lower pT.

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RHS versus $p^b_T$ for p + p collisions for four trigger selections.

RHS versus $p^b_T$ for Au + Au collisions for four trigger selections.


Strange meson enhancement in Pb Pb collisions

The NA44 collaboration Bearden, I. ; Bøggild, H. ; Boissevain, J. ; et al.
Phys.Lett.B 471 (1999) 6-12, 1999.
Inspire Record 504074 DOI 10.17182/hepdata.31360

The NA44 Collaboration has measured yields and differential distributions of K+, K-, pi+, pi- in transverse kinetic energy and rapidity, around the center-of-mass rapidity in 158 A GeV/c Pb+Pb collisions at the CERN SPS. A considerable enhancement of K+ production per pi is observed, as compared to p+p collisions at this energy. To illustrate the importance of secondary hadron rescattering as an enhancement mechanism, we compare strangeness production at the SPS and AGS with predictions of the transport model RQMD.

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Version 2
Global polarization measurement in Au+Au collisions

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 76 (2007) 024915, 2007.
Inspire Record 750410 DOI 10.17182/hepdata.98581

The system created in non-central relativistic nucleus-nucleus collisions possesses large orbital angular momentum. Due to spin-orbit coupling, particles produced in such a system could become globally polarized along the direction of the system angular momentum. We present the results of Lambda and anti-Lambda hyperon global polarization measurements in Au+Au collisions at sqrt{s_NN}=62.4 GeV and 200 GeV performed with the STAR detector at RHIC. The observed global polarization of Lambda and anti-Lambda hyperons in the STAR acceptance is consistent with zero within the precision of the measurements. The obtained upper limit, |P_{Lambda,anti-Lambda}| <= 0.02, is compared to the theoretical values discussed recently in the literature.

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Negative pion production in subthreshold heavy ion collisions

Suzuki, T. ; Fukuda, M. ; Ichihara, T. ; et al.
Phys.Lett.B 257 (1991) 27-31, 1991.
Inspire Record 324305 DOI 10.17182/hepdata.29463

Inclusive π − spectra have been measured for 14 N+C collisions at 41 A , 67 A , 80 A and 135 A MeV, the lowest energies measured for the charged pion. The cross sections fall exponentially with T π and the exponential slope factors at 90° in the nucleon-nucleon center of mass frame are determined. Energy distributions below a beam energy of 100 A MeV are less steep than expected from the monotonic decrease of the slope factor down to 100 A MeV. The production mechanism of energetic pions far below threshold is discussed for several models.

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Inclusive jet production in $p\bar{p}$ collisions

The D0 collaboration Abbott, B. ; Abdesselam, A. ; Abolins, M. ; et al.
Phys.Rev.Lett. 86 (2001) 1707-1712, 2001.
Inspire Record 536691 DOI 10.17182/hepdata.42948

We report a new measurement of the pseudorapidity (eta) and transverse-energy (Et) dependence of the inclusive jet production cross section in pbar b collisions at sqrt(s) = 1.8 TeV using 95 pb**-1 of data collected with the DZero detector at the Fermilab Tevatron. The differential cross section d^2sigma/dEt deta is presented up to |eta| = 3, significantly extending previous measurements. The results are in good overall agreement with next-to-leading order predictions from QCD and indicate a preference for certain parton distribution functions.

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Muon pair production in ep collisions at HERA

The H1 collaboration Aktas, A. ; Andreev, V. ; Anthonis, T. ; et al.
Phys.Lett.B 583 (2004) 28-40, 2004.
Inspire Record 632638 DOI 10.17182/hepdata.46338

Cross sections for the production of two isolated muons up to high di-muon masses are measured in ep collisions at HERA with the H1 detector in a data sample corresponding to an integrated luminosity of 71 pb^-1 at a centre of mass energy of sqrt{s} = 319 GeV. The results are in good agreement with Standard Model predictions, the dominant process being photon-photon interactions. Additional muons or electrons are searched for in events with two high transverse momentum muons using the full data sample corresponding to 114 pb^-1, where data at sqrt{s} = 301 GeV and sqrt{s} = 319 GeV are combined. Both the di-lepton sample and the tri-lepton sample agree well with the predictions.

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Coherent rho0 production in ultraperipheral heavy ion collisions

The STAR collaboration Adler, C. ; Ahammed, Z. ; Allgower, C. ; et al.
Phys.Rev.Lett. 89 (2002) 272302, 2002.
Inspire Record 588142 DOI 10.17182/hepdata.102319

The STAR collaboration reports the first observation of exclusive rho^0 photo-production, AuAu->AuAu rho^0, and rho^0 production accompanied by mutual nuclear Coulomb excitation, AuAu->Au*Au*rho^0, in ultra-peripheral heavy-ion collisions. The rho^0 have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at sqrt(s_NN)=130GeV agree with theoretical predictions treating rho^0 production and Coulomb excitation as independent processes.

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Strangeness Enhancement in Cu+Cu and Au+Au Collisions at $\sqrt{s_{NN}} = 200$ GeV

The STAR collaboration Agakishiev, G. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 108 (2012) 072301, 2012.
Inspire Record 918779 DOI 10.17182/hepdata.95886

We report new STAR measurements of mid-rapidity yields for the $\Lambda$, $\bar{\Lambda}$, $K^{0}_{S}$, $\Xi^{-}$, $\bar{\Xi}^{+}$, $\Omega^{-}$, $\bar{\Omega}^{+}$ particles in Cu+Cu collisions at \sNN{200}, and mid-rapidity yields for the $\Lambda$, $\bar{\Lambda}$, $K^{0}_{S}$ particles in Au+Au at \sNN{200}. We show that at a given number of participating nucleons, the production of strange hadrons is higher in Cu+Cu collisions than in Au+Au collisions at the same center-of-mass energy. We find that aspects of the enhancement factors for all particles can be described by a parameterization based on the fraction of participants that undergo multiple collisions.

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$K^0_S$ invariant mass spectra from Au+Au $\sqrt{s_{NN}} = 200$ GeV collisions, where $|y| < 0.5$. The uncertainties on the spectra points are statistical and systematic combined.

$\Lambda$ and $\bar{\Lambda}$ invariant mass spectra from Au+Au $\sqrt{s_{NN}} = 200$ GeV collisions, where $|y| < 0.5$. The $\Lambda$ and $\bar{\Lambda}$ yields have not been feed down subtracted from weak decays. The uncertainties on the spectra points are statistical and systematic combined.


Version 3
Deep sub-threshold $\phi$ production in Au+Au collisions

The HADES collaboration Adamczewski-Musch, J. ; Arnold, O. ; Behnke, C. ; et al.
Phys.Lett.B 778 (2018) 403-407, 2018.
Inspire Record 1519164 DOI 10.17182/hepdata.92099

We present data on charged kaons (K+-) and {\phi} mesons in Au(1.23A GeV)+Au collisions. It is the first simultaneous measurement of K and {\phi} mesons in central heavy-ion collisions below a kinetic beam energy of 10A GeV. The {\phi}/K- multiplicity ratio is found to be surprisingly high with a value of 0.52 +- 0.16 and shows no dependence on the centrality of the collision. Consequently, the different slopes of the K+ and K- transverse-mass spectra can be explained solely by feed- down, which substantially softens the spectra of K- mesons. Hence, in contrast to the commonly adapted argumentation in literature, the different slopes do not necessarily imply diverging freeze- out temperatures of K+ and K- mesons caused by different couplings to baryons.

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Kaon production in 200-GeV/nucleon nucleus-nucleus collisions

The HELIOS collaboration Akesson, T. ; Almehed, S. ; Angelis, A.L.S. ; et al.
Phys.Lett.B 296 (1992) 273-278, 1992.
Inspire Record 338072 DOI 10.17182/hepdata.28995

Results from the HELIOS External Spectrometer on kaon production in 200 GeV/ A S + W and p + W collisions are presented. The K π ratios are compared with results from a lower beam energy and are found to be remarkably similar. Evidence for secondary production of K + by meson-baryon rescattering is reviewed. Our results at y = 1.0–1.5 are compared with neutral strange particle results at midrapidity.

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Measurement of $K^+ K^-$ Production in $\gamma \gamma$ Collisions

The ARGUS collaboration Albrecht, H. ; Glaser, R. ; Harder, G. ; et al.
Z.Phys.C 48 (1990) 183-190, 1990.
Inspire Record 284561 DOI 10.17182/hepdata.15151

The production of charged kaon pairs in two-photon interactions has been studied with the ARGUS detector and the topological cross section has been measured. The γγ-widths and interference parameters have been determined for the tensor mesonsf2 (1270),a2 (1318) andf′2 (1525). The helicity structure assumed for the continuum contribution has a significant effect on the result. Upper limits have been obtained for the γγ-widths of the glueball candidate statesf2 (1720) andX (2230).

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Inclusive production of charged hadrons in photon-photon collisions

The OPAL collaboration Abbiendi, G. ; Ainsley, C. ; Akesson, P.F. ; et al.
Phys.Lett.B 651 (2007) 92-101, 2007.
Inspire Record 734955 DOI 10.17182/hepdata.48554

The inclusive production of charged hadrons in the collisions of quasi-real photons e+e- -> e+e- +X has been measured using the OPAL detector at LEP. The data were taken at e+e- centre-of-mass energies from 183 to 209 GeV. The differential cross-sections as a function of the transverse momentum and the pseudorapidity of the hadrons are compared to theoretical calculations of up to next-to-leading order (NLO) in the strong coupling constant alpha{s}. The data are also compared to a measurement by the L3 Collaboration, in which a large deviation from the NLO predictions is observed.

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Inclusive charm production in two photon collisions at LEP

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 453 (1999) 83-93, 1999.
Inspire Record 481163 DOI 10.17182/hepdata.49252

The cross section of charm production in γγ collisions σ(e + e − →e + e − c c ̄ X) is measured at LEP with the L3 detector at centre-of-mass energies from 91 GeV to 183 GeV. Charmed hadrons are identified by electrons and muons from semileptonic decays. The direct process γγ→c c ̄ is found to be insufficient to describe the data. The measured cross section values and event distributions require contributions from resolved processes, which are sensitive to the gluon density in the photon.

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Centrality and pseudorapidity dependence of charged hadron production at intermediate $p_{T}$ in Au + Au collisions at $\sqrt{s_{NN}}$ = 130-GeV

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 70 (2004) 044901, 2004.
Inspire Record 648464 DOI 10.17182/hepdata.98858

We present STAR measurements of charged hadron production as a function of centrality in Au + Au collisions at sqrt(s_NN) = 130 GeV. The measurements cover a phase space region of 0.2 < p_T < 6.0 GeV/c in transverse momentum and -1 < eta < 1 in pseudorapidity. Inclusive transverse momentum distributions of charged hadrons in the pseudorapidity region 0.5 < |eta| < 1 are reported and compared to our previously published results for |eta| < 0.5. No significant difference is seen for inclusive p_T distributions of charged hadrons in these two pseudorapidity bins. We measured dN/deta distributions and truncated mean p_T in a region of p_T > p_T^cut, and studied the results in the framework of participant and binary scaling. No clear evidence is observed for participant scaling of charged hadron yield in the measured p_T region. The relative importance of hard scattering process is investigated through binary scaling fraction of particle production.

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Ratio of the number of participants Npart or the number of binary collisions Nbin determined from different models to that from Monte Carlo Glauber calculation.

Ratio of the number of participants Npart or the number of binary collisions Nbin determined from different models to that from Monte Carlo Glauber calculation.


Pion, kaon, proton and anti-proton transverse momentum distributions from $p + p$ and $d +$ Au collisions at $\sqrt{s_{NN}} = 200$GeV

The STAR collaboration Adams, John ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Lett.B 616 (2005) 8-16, 2005.
Inspire Record 628232 DOI 10.17182/hepdata.98859

Identified mid-rapidity particle spectra of $\pi^{\pm}$, $K^{\pm}$, and $p(\bar{p})$ from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor ($R_{dAu}$) between protons $(p+\bar{p})$ and charged hadrons ($h$) in the transverse momentum range $1.2<{p_{T}}<3.0$ GeV/c is measured to be $1.19\pm0.05$(stat)$\pm0.03$(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of $(p+\bar{p})/h$ in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.

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Minimum-bias ratios of protons (p+$\bar{p}$) over inclusive charged hadrons (h) at -0.5 $<$ $\eta$ 0.0 from $\sqrt{s} = 200 GeV$ p+p, d+Au and $\sqrt{s}$ = 130 GeV AuAu collisions. Errors are statistical.


Total cross-section in $\gamma \gamma$ collisions at LEP

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 519 (2001) 33-45, 2001.
Inspire Record 552997 DOI 10.17182/hepdata.49853

The reaction e+e- -> e+e- gamma* gamma* -> e+e- hadrons for quasi-real photons is studied using data from root(s) = 183 GeV up to 202 GeV. Results on the total cross sections sigma(e+e- -> e+e- hadrons) and sigma(+e- gamma* gamma* -> e+e- hadrons) are given for the two-photon centre-of-mass energies 5 GeV &lt; Wgammagamma &lt; 185 GeV. The total cross section of two real photons is described by a Regge parametrisation. We observe a steeper rise with the two-photon centre-of-mass energy as compared to the hadron-hadron and the photon-proton cross sections. The data are also compared to the expectations of different theoretical models.

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Inclusive jet production in two-photon collisions at LEP

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 602 (2004) 157-166, 2004.
Inspire Record 661114 DOI 10.17182/hepdata.48848

Inclusive jet production, e+e- -> e+e- \ee$ jet X, is studied using 560/pb of data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 209 GeV. The inclusive differential cross section is measured using a k_t jet algorithm as a function of the jet transverse momentum, pt, in the range 3&lt;pt&lt;50 GeV for a pseudorapidity, eta, in the range -1&lt;eta&lt;1. This cross section is well represented by a power law. For high pt, the measured cross section is significantly higher than the NLO QCD predictions, as already observed for inclusive charged and neutral pion production.

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Inclusive lambda production in two photon collisions at LEP

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 586 (2004) 140-150, 2004.
Inspire Record 637287 DOI 10.17182/hepdata.48849

The reactions e^+e^- -> e^+e^- Lambda X and e^+e^- -> e^+e^- Lambda X are studied using data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 209 GeV. Inclusive differential cross sections are measured as a function of the lambda transverse momentum, p_t, and pseudo-rapidity, eta, in the ranges 0.4 GeV < p_t < 2.5 GeV and |\eta| < 1.2. The data are compared to Monte Carlo predictions. The differential cross section as a function of p_t is well described by an exponential of the form A exp (- p_t / <p_t>)$.

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Double tag events in two photon collisions at LEP

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 531 (2002) 39-51, 2002.
Inspire Record 565440 DOI 10.17182/hepdata.49820

Double-tag events in two-photon collisions are studied using the L3 detector at LEP centre-of-mass energies from root(s)=189 GeV to 209 GeV. The cross sections of the e+e- -> e+e- hadrons and gamma*gamma* -> hadrons processes are measured as a function of the photon virtualities, Q1^2 and Q2^2, of the two-photon mass, W_gammagamma, and of the variable Y=ln(W_gammagamma^2/(Q1 Q2)), for an average photon virtuality &lt;Q2> = 16 GeV2. The results are in agreement with next-to-leading order calculations for the process gamma*gamma* -> q qbar in the interval 2 &lt;= Y &lt;= 5. An excess is observed in the interval 5 &lt; Y &lt;= 7, corresponding to W_gammagamma greater than 40 GeV . This may be interpreted as a sign of resolved photon QCD processes or the onset of BFKL phenomena.

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Inclusive $D^{*+-}$ production in two photon collisions at LEP

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 535 (2002) 59-69, 2002.
Inspire Record 585623 DOI 10.17182/hepdata.54885

Inclusive D^{*+-} production in two-photon collisions is studied with the L3 detector at LEP, using 683 pb^{-1} of data collected at centre-of-mass energies from 183 to 208 GeV. Differential cross sections are determined as functions of the transverse momentum and pseudorapidity of the D^{*+-} mesons in the kinematic region 1 GeV &lt; P_T &lt; 12 GeV and |eta| &lt; 1.4. The cross sections sigma(e^+e^- -> e^+e^-D^{*+-}X) in this kinematical region is measured and the sigma(e^+e^- -> e^+e^- cc{bar}X) cross section is derived. The measurements are compared with next-to-leading order perturbative QCD calculations.

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Charged particle multiplicities in nuclear collisions at 200-GeV/N

The NA35 collaboration Bächler, J. ; Bartke, J. ; Bialkowska, H. ; et al.
Z.Phys.C 51 (1991) 157-162, 1991.
Inspire Record 320907 DOI 10.17182/hepdata.14983

Data on multiplicities of charged particles produced in proton-nucleus and nucleus-nucleus collisions at 200 GeV per nucleon are presented. It is shown that the mean multiplicity of negative particles is proportional to the mean number of nucleons participating in the collision both for nucleus-nucleus and proton-nucleus collisions. The apparent consistency of pion multiplicity data with the assumption of an incoherent superposition of nucleon-nucleon collisions is critically discussed.

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Hyperon production in proton - sulphur collisions at 200-GeV/c

The WA94 collaboration Abatzis, S ; Andersen, E ; Andrighetto, A ; et al.
Phys.Lett.B 400 (1997) 239-244, 1997.
Inspire Record 427129 DOI 10.17182/hepdata.12547

The WA94 experiment uses the production of strange particles and antiparticles to investigate the properties of hot hadronic matter created in heavy-ion interactions. Λ, Λ , Ξ − and Ξ + particle yields and transverse mass spectra are presented for pS interactions. These results are compared with those from SS interactions. Our results are also compared with those from pW and SW interactions of the WA85 experiment.

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High p(t) Direct Photon Production in p p Collisions

Anassontzis, E. ; Karabarbounis, A. ; Kourkoumelis, C. ; et al.
Z.Phys.C 13 (1982) 277-289, 1982.
Inspire Record 176956 DOI 10.17182/hepdata.16410

Direct photon and neutral-pion production have been measured inpp collisions at the CERN ISR for 30<\(\sqrt s \)<63 GeV and transverse momenta up to 12 GeV/c. The direct photon signal relative to neutral-pion production increases withpT and shows little\(\sqrt s \)-dependence. Results are reported from a variety of running conditions, and details are given on the method of analysis and on the evaluation of systematic errors for the inclusive cross-section of single-photon and neutral-pion production.

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Sigma production in p-p collisions at 5 GeV/ c

Sondhi, I. ;
Phys.Lett.B 26 (1968) 645-648, 1968.
Inspire Record 1389658 DOI 10.17182/hepdata.29305

The cross section for the reaction pp → Σ + K + n at 5 GeV/ c is measured to be 48.1 ± 3.5 μ b. The KΣ mass spectrum shows an enhancement at 1.86 GeV, which may due to the Δ (1920) resonance. Adequacy of the one-pion exchange model for the reaction is discussed. The cross section for the reaction pp → Σ + K o p is found to be 24.9 ± 2.3 μ b.

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