Pi p elastic scattering from 88 to 292 mev

Bussey, P.J. ; Carter, J.R. ; Dance, D.R. ; et al.
Nucl.Phys.B 58 (1973) 363-377, 1973.
Inspire Record 83985 DOI 10.17182/hepdata.6770

Differential cross sections for π + p and π − p elastic scattering have been measured with an accuracy of typically ±2% at 10 and 9 energies respectively in the range 88 to 292 MeV of lab kinetic energy.

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Pion-Nucleon Total Cross Sections from 0.5 to 2.65 GeV/c

Carter, A.A. ; Riley, K.F. ; Tapper, R.J. ; et al.
Phys.Rev. 168 (1968) 1457-1465, 1968.
Inspire Record 54182 DOI 10.17182/hepdata.250

Total cross sections of π+ and π− mesons on protons and deuterons have been measured in a transmission experiment to relative accuracies of ±0.2% over the laboratory momentum range 0.46-2.67 GeV/c. The systematic error is estimated to be about ±0.5% over most of the range, increasing to about ±2% near both ends. Data have been obtained at momentum intervals of 25-50 MeV/c with a momentum resolution of ±0.6%. No new structure is observed in the π±p total cross sections, but results differ in several details from previous experiments. From 1-2 GeV/c, where systematic erros are the smallest, the total cross section of π− mesons on deuterons is found to be consistently higher than that of π+ mesons by (1.3±0.3)%; about half of this difference may be understood in terms of Coulomb-barrier effects. The πd and πN total cross sections are used to check the validity of the Glauber theory. Substantial disagreements (up to 2 mb) are observed, and the conclusion is drawn that the Glauber theory is inadequate in this momentum range.

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The total cross-sections for pion-proton scattering between 70 mev and 290 mev

Carter, A.A. ; Williams, J.R. ; Bugg, D.V. ; et al.
Nucl.Phys.B 26 (1971) 445-460, 1971.
Inspire Record 68771 DOI 10.17182/hepdata.21874

Measurements have been made of the π ∓ proton total cross sections over the laboratory kinetic energy range 70 to 290 MeV. The absolute accuracy of the data is generally 0.5 %, but decreases to 1 % for some points where applied corrections are large or where low particle fluxes limit the statistical accuracy.

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The pi- p ---> pi0 n charge-exchange cross-sections between 90 mev and 290 mev

Bugg, D.V. ; Bussey, P.J. ; Dance, D.R. ; et al.
Nucl.Phys.B 26 (1971) 588-596, 1971.
Inspire Record 68770 DOI 10.17182/hepdata.21877

Measurements have been made of the total charge-exchange cross section π − p to π 0 n over the laboratory kinetic energy range 90 to 290 MeV. The data have an absolute accuracy of typically 1%, and have here been used to determine the pion-nucleon P 13 phase shift.

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Mass identified particle production in $p\bar{p}$ collisions at $\sqrt{s}$ = 300-GeV, 540-GeV, 1000-GeV, and 1800-GeV

The E735 collaboration Alexopoulos, T. ; Allen, C. ; Anderson, E.W. ; et al.
Phys.Rev.D 48 (1993) 984-997, 1993.
Inspire Record 363171 DOI 10.17182/hepdata.22669

The yields and average transverse momenta of pions, kaons, and antiprotons produced at the Fermilab p¯p collider at s=300, 540, 1000, and 1800 GeV are presented and compared with data from the energies reached at the CERN collider. We also present data on the dependence of average transverse momentum 〈pt〉 and particle ratios as a function of charged particle density dNcdη; data for particle densities as high as six times the average value, corresponding to a Bjorken energy density 6 GeV/fm3, are reported. These data are relevant to the search for quark-gluon phase of QCD.

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Production of Four Prong Final States in Photon-photon Collisions

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.D 37 (1988) 28, 1988.
Inspire Record 261630 DOI 10.17182/hepdata.3824

Results are presented on the exclusive production of four-prong final states in photon-photon collisions from the TPC/Two-Gamma detector at the SLAC e+e− storage ring PEP. Measurement of dE/dx and momentum in the time-projection chamber (TPC) provides identification of the final states 2π+2π−, K+K−π+π−, and 2K+2K−. For two quasireal incident photons, both the 2π+2π− and K+K−π+π− cross sections show a steep rise from threshold to a peak value, followed by a decrease at higher mass. Cross sections for the production of the final states ρ0ρ0, ρ0π+π−, and φπ+π− are presented, together with upper limits for φρ0, φφ, and K*0K¯ *0. The ρ0ρ0 contribution dominates the four-pion cross section at low masses, but falls to nearly zero above 2 GeV. Such behavior is inconsistent with expectations from vector dominance but can be accommodated by four-quark resonance models or by t-channel factorization. Angular distributions for the part of the data dominated by ρ0ρ0 final states are consistent with the production of JP=2+ or 0+ resonances but also with isotropic (nonresonant) production. When one of the virtual photons has mass (mγ2=-Q2≠0), the four-pion cross section is still dominated by ρ0ρ0 at low final-state masses Wγγ and by 2π+2π− at higher mass. Further, the dependence of the cross section on Q2 becomes increasingly flat as Wγγ increases.

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Measurement of the polarized structure function sigma(LT-prime) for pion electroproduction in the Roper resonance region

The CLAS collaboration Joo, K. ; Smith, L.C. ; Aznauryan, I.G. ; et al.
Phys.Rev.C 72 (2005) 058202, 2005.
Inspire Record 681275 DOI 10.17182/hepdata.25214

The polarized longitudinal-transverse structure function $\sigma_{LT^\prime}$ measures the interference between real and imaginary amplitudes in pion electroproduction and can be used to probe the coupling between resonant and non-resonant processes. We report new measurements of $\sigma_{LT^\prime}$ in the $N(1440){1/2}^+$ (Roper) resonance region at $Q^2=0.40$ and 0.65 GeV$^2$ for both the $\pi^0 p$ and $\pi^+ n$ channels. The experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally polarized electrons at a beam energy of 1.515 GeV. Complete angular distributions were obtained and are compared to recent phenomenological models. The $\sigma_{LT^\prime}(\pi^+ n)$ channel shows a large sensitivity to the Roper resonance multipoles $M_{1-}$ and $S_{1-}$ and provides new constraints on models of resonance formation.

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Measurement of the pi- p ---> 3 pi0 n total cross-section from threshold to 0.75-GeV/c

Starostin, A. ; Nefkens, B.M.K. ; Manley, D.M. ; et al.
Phys.Rev.C 67 (2003) 068201, 2003.
Inspire Record 620818 DOI 10.17182/hepdata.25279

We report a new measurement of the π−p→3π0n total cross section from threshold to pπ=0.75GeV/c. The cross section near the N(1535)12− resonance is only a few μb after subtracting the large η→3π0 background associated with π−p→ηn. A simple analysis of our data results in the estimated branching fraction B[S11→πN(1440)12+]=(8±2)%. This is the first such estimate obtained with a three-pion production reaction.

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Measurement of pi- p ---> pi0 pi0 n from threshold to p(pi-) 750-MeV/c

The Crystal Ball collaboration Prakhov, S. ; Nefkens, B.M.K. ; Allgower, C.E. ; et al.
Phys.Rev.C 69 (2004) 045202, 2004.
Inspire Record 647544 DOI 10.17182/hepdata.25355

Reaction π−p→π0π0n has been measured with high statistics in the beam momentum range 270–750MeV∕c. The data were obtained using the Crystal Ball multiphoton spectrometer, which has 93% of 4π solid angle coverage. The dynamics of the π−p→π0π0n reaction and the dependence on the beam energy are displayed in total cross sections, Dalitz plots, invariant-mass spectra, and production angular distributions. Special attention is paid to the evaluation of the acceptance that is needed for the precision determination of the total cross section σt(π−p→π0π0n). The energy dependence of σt(π−p→π0π0n) shows a shoulder at the Roper resonance [i.e., the N(1440)12+], and there is also a maximum near the N(1520)32−. It illustrates the importance of these two resonances to the π0π0 production process. The Dalitz plots are highly nonuniform; they indicate that the π0π0n final state is dominantly produced via the π0Δ0(1232) intermediate state. The invariant-mass spectra differ much from the phase-space distributions. The production angular distributions are also different from the isotropic distribution, and their structure depends on the beam energy. For beam momenta above 550MeV∕c, the density distribution in the Dalitz plots strongly depends on the angle of the outgoing dipion system (or equivalently on the neutron angle). The role of the f0(600) meson (also known as the σ) in π0π0n production remains controversial.

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Backward electroproduction of pi0 mesons on protons in the region of nucleon resonances at four momentum transfer squared Q**2 = 1.0-GeV**2

The JLab Hall A collaboration Laveissiere, G. ; Degrande, N. ; Jaminion, S. ; et al.
Phys.Rev.C 69 (2004) 045203, 2004.
Inspire Record 625669 DOI 10.17182/hepdata.25226

Exclusive electroproduction of pi0 mesons on protons in the backward hemisphere has been studied at Q**2 = 1.0 GeV**2 by detecting protons in the forward direction in coincidence with scattered electrons from the 4 GeV electron beam in Jefferson Lab's Hall A. The data span the range of the total (gamma* p) center-of-mass energy W from the pion production threshold to W = 2.0 GeV. The differential cross sections sigma_T+epsilon*sigma_L, sigma_TL, and sigma_TT were separated from the azimuthal distribution and are presented together with the MAID and SAID parametrizations.

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The $e^+e^- \to 3(\pi^+ \pi^-), 2(\pi^+ \pi^- \pi^0)$ and $K^+ K^- 2(\pi^+ \pi^-)$ cross sections at center-of-mass energies from production threshold to 4.5-GeV measured with initial-state radiation

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Boutigny, D. ; et al.
Phys.Rev.D 73 (2006) 052003, 2006.
Inspire Record 709730 DOI 10.17182/hepdata.41843

We study the processes e+ e- --> 3(pi+pi-)gamma, 2(pi+pi-pi0)gamma and K+ K- 2(pi+pi-)gamma, with the photon radiated from the initial state. About 20,000, 33,000 and 4,000 fully reconstructed events, respectively, have been selected from 232 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy, so that these data can be compared with the corresponding direct e+e- measurements. From the 3(pi+pi-), 2(pi+pi-pi0) and K+ K- 2(pi+pi-) mass spectra, the cross sections for the processes e+ e- --> 3(pi+pi-), e+ e- --> 2(pi+pi-pi0) and e+ e- --> K+ K- 2(pi+pi-) are measured for center-of-mass energies from production threshold to 4.5 GeV. The uncertainty in the cross section measurement is typically 6-15%. We observe the J/psi in all these final states and measure the corresponding branching fractions.

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Pion and Kaon Pair Production in Photon-Photon Collisions

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.Lett. 57 (1986) 404, 1986.
Inspire Record 228072 DOI 10.17182/hepdata.20204

We report measurements of the two-photon processes e+e−→e+e−π+π− and e+e−→e+e−K+K−, at an e+e− center-of-mass energy of 29 GeV. In the π+π− data a high-statistics analysis of the f(1270) results in a γγ width Γ(γγ→f)=3.2±0.4 keV. The π+π− continuum below the f mass is well described by a QED Born approximation, whereas above the f mass it is consistent with a QCD-model calculation if a large contribution from the f is assumed. For the K+K− data we find agreement of the high-mass continuum with the QCD prediction; limits on f′(1520) and θ(1720) formation are presented.

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Inclusive Lambda(c)+ Production in e+ e- Annihilations at s**(1/2) = 10.54-GeV and in Upsilon(4S) Decays

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
Phys.Rev.D 75 (2007) 012003, 2007.
Inspire Record 725377 DOI 10.17182/hepdata.22089

We present measurements of the total production rates and momentum distributions of the charmed baryon $\Lambda_c^+$ in $e^+e^- \to$ hadrons at a center-of-mass energy of 10.54 GeV and in $\Upsilon(4S)$ decays. In hadronic events at 10.54 GeV, charmed hadrons are almost exclusively leading particles in $e^+e^- \to c\bar{c}$ events, allowing direct studies of $c$-quark fragmentation. We measure a momentum distribution for $\Lambda_c^+$ baryons that differs significantly from those measured previously for charmed mesons. Comparing with a number of models, we find none that can describe the distribution completely. We measure an average scaled momentum of $\left< x_p \right> = 0.574\pm$0.009 and a total rate of $N_{\Lambda c}^{q\bar{q}} = 0.057\pm$0.002(exp.)$\pm$0.015(BF) $\Lambda_c^+$ per hadronic event, where the experimental error is much smaller than that due to the branching fraction into the reconstructed decay mode, $pK^-\pi^+$. In $\Upsilon (4S)$ decays we measure a total rate of $N_{\Lambda c}^{\Upsilon} = 0.091\pm$0.006(exp.)$\pm$0.024(BF) per $\Upsilon(4S)$ decay, and find a much softer momentum distribution than expected from B decays into a $\Lambda_c^+$ plus an antinucleon and one to three pions.

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The $e^+e^- \to \pi^+ \pi^- \pi^+ \pi^-$, $K^+ K^- \pi^+ \pi^-$, and $K^+ K^- K^+ K^-$ cross sections at center-of-mass energies 0.5-GeV - 4.5-GeV measured with initial-state radiation

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Boutigny, D. ; et al.
Phys.Rev.D 71 (2005) 052001, 2005.
Inspire Record 676691 DOI 10.17182/hepdata.22111

We study the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-\gamma$, with a hard photon radiated from the initial state. About 60,000 fully reconstructed events have been selected from 89 $fb^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that these data can be compared with the corresponding direct $e^+e^-$ measurements. From the $4\pi$-mass spectrum, the cross section for the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-$ is measured for center-of-mass energies from 0.6 to 4.5 $GeV/c^2$. The uncertainty in the cross section measurement is typically 5%. We also measure the cross sections for the final states $K^+ K^- \pi^+\pi^-$ and $K^+ K^- K^+ K^-$. We observe the $J/\psi$ in all three final states and measure the corresponding branching fractions. We search for X(3872) in $J/\psi (\to\mu^+\mu^-) \pi^+\pi^-$ and obtain an upper limit on the product of the $e^+e^-$ width of the X(3872) and the branching fraction for $X(3872) \to J/\psi\pi^+\pi^-$.

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Backward-angle electron-proton elastic scattering and proton electromagnetic form-factors

Price, L.E. ; Dunning, J.R. ; Goitein, M. ; et al.
Phys.Rev.D 4 (1971) 45-53, 1971.
Inspire Record 67836 DOI 10.17182/hepdata.23074

Elastic electron-proton scattering cross sections were measured at backward angles (80°-90°) in the laboratory for four-momentum transfers between 7 F−2 and 45 F−2. Experimental errors range from 3.1% to 5.3%, including a systematic error estimated to be 1.9% added in quadrature. Electric and magnetic form factors are computed from all the recent data in this q2 range, with allowance made for possible normalization differences. The results show a deviation from the scaling law.

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Inclusive hadron photoproduction from longitudinally polarized protons and deuterons

The E155 collaboration Anthony, P.L. ; Arnold, R.G. ; Averett, T. ; et al.
Phys.Lett.B 458 (1999) 536-544, 1999.
Inspire Record 495554 DOI 10.17182/hepdata.28074

We report measurements of the asymmetry A_parallel for inclusive hadron production on longitudinally polarized proton and deuteron targets by circularly polarized photons. The photons were produced via internal and external bremsstrahlung from an electron beam of 48.35 GeV. Asymmetries for both positive and negative signed hadrons, and a subset of identified pions, were measured in the momentum range 10<P<30 GeV at 2.75 and 5.5 degrees. Small non-zero asymmetries are observed for the proton, while the deuteron results are consistent with zero. Recent calculations do not describe the data well.

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The e+ e- ---> 2(pi+ pi-) pi0, 2(pi+ pi-) eta, K+ K- pi+ pi- pi0 and K+ K- pi+ pi- eta Cross Sections Measured with Initial-State Radiation

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
Phys.Rev.D 76 (2007) 092005, 2007.
Inspire Record 758568 DOI 10.17182/hepdata.51824

We study the processes $e^+ e^-\to 2(\pi^+\pi^-)\pi^0\gamma$, $2(\pi^+\pi^-)\eta\gamma$, $K^+ K^-\pi^+\pi^-\pi^0\gamma$ and $K^+ K^-\pi^+\pi^-\eta\gamma$ with the hard photon radiated from the initial state. About 20000, 4300, 5500 and 375 fully reconstructed events, respectively, are selected from 232 fb$^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective $e^+ e^-$ center-of-mass energy, so that the obtained cross sections from the threshold to about 5 GeV can be compared with corresponding direct \epem measurements, currently available only for the $\eta\pi^+\pi^-$ and $\omega\pi^+\pi^-$ submodes of the $e^+ e^-\to 2(\pi^+\pi^-)\pi^0$ channel. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from $e^+ e^-\to\omega(782)\pi^+\pi^-$ and study the $\omega(1420)$ and $\omega(1650)$ resonances. In the charmonium region, we observe the $J/\psi$ in all these final states and several intermediate states, as well as the $\psi(2S)$ in some modes, and we measure the corresponding branching fractions.

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Polarization Parameters in Positive Pion Photoproduction

Bussey, P.J. ; Raine, C. ; Rutherglen, J.G. ; et al.
Nucl.Phys.B 154 (1979) 205-225, 1979.
Inspire Record 140382 DOI 10.17182/hepdata.43832

Measurements have been made of the polarisation parameters Σ , T and P for the process γ p → π + n in the photon energy range 520–2250 MeV at c.m. angles between 30° and 120°. These data were obtained in a double polarisation experiment, using the polarised photon beam from the Daresbury electron synchrotron incident on a polarised proton target. The data are compared with predictions from current theoretical analyses.

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Measurements of $e^{+} e^{-} \to K^{+} K^{-} \eta$, $K^{+} K^{-} \pi^0$ and $K^0_{s} K^\pm \pi^\mp$ cross- sections using initial state radiation events

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
Phys.Rev.D 77 (2008) 092002, 2008.
Inspire Record 765258 DOI 10.17182/hepdata.50372

This paper reports measurements of processes: e+e- -> gamma KsK+pi-, e+e- -> gamma K+K-pi0, e+e- -> gamma phi eta, and e+e- -> gamma phi pi0. The initial state radiated photon allows to cover the hadronic final state in the energy range from thresholds up to ~4.6 GeV. The overall size of the data sample analyzed is 232 fb-1, collected by the BaBar detector running at the PEP-II e+e- storage ring. From the Dalitz plot analysis of the KsK+pi- final state, moduli and relative phase of the isoscalar and the isovector components of the e+e- -> K K*(892) cross section are determined. Parameters of phi and rho recurrences are also measured, using a global fitting procedure which exploits the interconnection among amplitudes, moduli and phases of the e+e- -> KsK+pi-, K+K-pi0, phi eta final states. The cross section for the OZI-forbidden process e+e- -> phi pi0, and the J/psi branching fractions to KK*(892) and K+K-eta are also measured.

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Cross Sections for the Reactions e+e- --> K+ K- pi+pi-, K+ K- pi0pi0, and K+ K- K+ K- Measured Using Initial-State Radiation Events

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Prencipe, E. ; et al.
Phys.Rev.D 86 (2012) 012008, 2012.
Inspire Record 892684 DOI 10.17182/hepdata.62222

We study the processes e+e- --> K+ K- pi+pi-gamma, K+ K- pi0pi0gamma, and K+ K- K+ K-gamma, where the photon is radiated from the initial state. About 84000, 8000, and 4200 fully reconstructed events, respectively, are selected from 454 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the \epem center-of-mass energy, so that the K+ K- pi+pi- data can be compared with direct measurements of the e+e- --> K+ K- pi+pi- reaction. No direct measurements exist for the e+e- --> K+ K-pi0pi0 or e+e- --> K+ K-K+ K- reactions, and we present an update of our previous result with doubled statistics. Studying the structure of these events, we find contributions from a number of intermediate states, and extract their cross sections. In particular, we perform a more detailed study of the e+e- --> phi(1020)pipigamma reaction, and confirm the presence of the Y(2175) resonance in the phi(1020) f0(980) and K+K-f0(980) modes. In the charmonium region, we observe the J/psi in all three final states and in several intermediate states, as well as the psi(2S) in some modes, and measure the corresponding product of branching fraction and electron width.

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A Kinematically complete measurement of the proton structure function F(2) in the resonance region and evaluation of its moments

The CLAS collaboration Osipenko, M. ; Ricco, G. ; Taiuti, M. ; et al.
Phys.Rev.D 67 (2003) 092001, 2003.
Inspire Record 612145 DOI 10.17182/hepdata.12253

We measured the inclusive electron-proton cross section in the nucleon resonance region (W < 2.5 GeV) at momentum transfers Q**2 below 4.5 (GeV/c)**2 with the CLAS detector. The large acceptance of CLAS allowed for the first time the measurement of the cross section in a large, contiguous two-dimensional range of Q**2 and x, making it possible to perform an integration of the data at fixed Q**2 over the whole significant x-interval. From these data we extracted the structure function F2 and, by including other world data, we studied the Q**2 evolution of its moments, Mn(Q**2), in order to estimate higher twist contributions. The small statistical and systematic uncertainties of the CLAS data allow a precise extraction of the higher twists and demand significant improvements in theoretical predictions for a meaningful comparison with new experimental results.

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