Measurement of prompt hadron production ratios in $pp$ collisions at $\sqrt{s} = $ 0.9 and 7 TeV

The LHCb collaboration Aaij, R ; Abellan Beteta, C ; Adametz, A ; et al.
Eur.Phys.J.C 72 (2012) 2168, 2012.
Inspire Record 1119400 DOI 10.17182/hepdata.59495

The charged-particle production ratios $\bar{p}/p$, $K^-/K^+$, $\pi^-/\pi^+$, $(p + \bar{p})/(\pi^+ + \pi^-)$, $(K^+ + K^-)/(\pi^+ + \pi^-)$ and $(p + \bar{p})/(K^+ + K^-)$ are measured with the LHCb detector using $0.3 {\rm nb^{-1}}$ of $pp$ collisions delivered by the LHC at $\sqrt{s} = 0.9$ TeV and $1.8 {\rm nb^{-1}}$ at $\sqrt{s} = 7$ TeV. The measurements are performed as a function of transverse momentum $p_{\rm T}$ and pseudorapidity $\eta$. The production ratios are compared to the predictions of several Monte Carlo generator settings, none of which are able to describe adequately all observables. The ratio $\bar{p}/p$ is also considered as a function of rapidity loss, $\Delta y \equiv y_{\rm beam} - y$, and is used to constrain models of baryon transport.

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Production of $\phi$ and F (1970) $\to \phi \pi$ in $e^+ e^-$ Annihilation at 29-{GeV}

Derrick, M. ; Fernandez, E. ; Fries, R. ; et al.
Phys.Rev.Lett. 54 (1985) 2568, 1985.
Inspire Record 213242 DOI 10.17182/hepdata.20340

Data from the high-resolution spectrometer at PEP have been used to study the inclusive production of φ mesons and F± mesons decaying into φπ±. Fragmentation functions and cross sections are presented and compared to existing data. The total φ cross section at 29 GeV is 40±6 pb. The observed F signal in the region z>0.4, given the assumption that R(F)[R(F)+R(D)]=0.15, corresponds to an F→φπ branching ratio of (3.3±1.1)%. The measured F mass is 1963±3±3 MeV/c2.

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K*0 AND K0(S) MESON PRODUCTION IN e+ e- ANNIHILATIONS AT 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Badtke, D.H. ; et al.
Phys.Rev.Lett. 53 (1984) 2378, 1984.
Inspire Record 205869 DOI 10.17182/hepdata.20408

The inclusive production cross sections and transverse momentum distributions of K*0 and KS0 mesons in e+e− annihilation at a center-of-mass energy of 29 GeV have been measured by means of the time projection chamber detector in the PEP-4 experiment. The mean multiplicites are found to be 0.49 ± 0.04(stat.) ± 0.07(syst.) (K*0+K―*0) and 1.22 ± 0.03(stat.) ±0.15(syst.) (K0+K―0) per event.

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Test of spin dependence in charm-quark fragmentation to D*.

The TPC/Two-Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.D 43 (1991) 29-33, 1991.
Inspire Record 316132 DOI 10.17182/hepdata.22830

We have measured the polarization of D*, the energy dependence of the polarization, and the spin-density matrix of D* in e+e− annihilation at a center-of-mass energy of 29 GeV using the Time Projection Chamber detector at the SLAC storage ring PEP. In 147 pb−1 of data we see no strong evidence for polarization, alignment, or final-state interactions in this fragmentation process.

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Measurement of very forward neutron energy spectra for 7 TeV proton--proton collisions at the Large Hadron Collider

The LHCf collaboration Adriani, O. ; Berti, E. ; Bonechi, L. ; et al.
Phys.Lett.B 750 (2015) 360-366, 2015.
Inspire Record 1351909 DOI 10.17182/hepdata.73320

The Large Hadron Collider forward (LHCf) experiment is designed to use the LHC to verify the hadronic-interaction models used in cosmic-ray physics. Forward baryon production is one of the crucial points to understand the development of cosmic-ray showers. We report the neutron-energy spectra for LHC $\sqrt{s}$ = 7 TeV proton--proton collisions with the pseudo-rapidity $\eta$ ranging from 8.81 to 8.99, from 8.99 to 9.22, and from 10.76 to infinity. The measured energy spectra obtained from the two independent calorimeters of Arm1 and Arm2 show the same characteristic feature before unfolding the difference in the detector responses. We unfolded the measured spectra by using the multidimensional unfolding method based on Bayesian theory, and the unfolded spectra were compared with current hadronic-interaction models. The QGSJET II-03 model predicts a high neutron production rate at the highest pseudo-rapidity range similar to our results and the DPMJET 3.04 model describes our results well at the lower pseudo-rapidity ranges. However no model perfectly explains the experimental results in the whole pseudo-rapidity range. The experimental data indicate the most abundant neutron production rate relative to the photon production, which does not agree with predictions of the models.

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Cross-Sections and Charged Multiplicity Distributions for pi+ p, K+ p and p p Interactions at 250-GeV/c

The NA22 collaboration Adamus, M. ; Agababyan, N.M. ; Ajinenko, I.V. ; et al.
Z.Phys.C 32 (1986) 475, 1986.
Inspire Record 18431 DOI 10.17182/hepdata.15845

Cross sections and charged multiplicity distributions for π+p,K+p andpp interactions at 250 GeV/c are presented and compared to each other as well as to earlier (for π+p andK+p lower energy) data. Consistently, the meson-proton (M+p) data have narrower multiplicity distributions and higher average multiplicity thanpp data. Up to our energy, generalized KNO functions describe the energy dependence of the shape of the multiplity distribution with one parameter forM+p and one forpp collisions. If interpreted in terms of negative binomials, the parameter 1/k tends to be slightly lower forM+p than forpp data. For both types of hadron-hadron collision, 1/k is larger than fore+e− andlp collisions.

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CHARGED D* MESON PRODUCTION IN e+ e- ANNIHILATION AT S**(1/2) = 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Armitage, J.C. ; et al.
Phys.Rev.D 34 (1986) 1945, 1986.
Inspire Record 217416 DOI 10.17182/hepdata.23509

The production of charmed D* mesons in e+e− annihilations at a center-of-mass energy of 29 GeV has been studied using the time-projection-chamber (TPC) detector at the SLAC storage ring PEP. The production cross section, fragmentation function, and forward-backward asymmetry due to electroweak effects are measured, and a limit on D0-D¯0 mixing is determined.

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Hadron Production in $e^+ e^-$ Annihilation at $\sqrt{s}=29$-{GeV}

Derrick, M. ; Fernandez, E. ; Fries, R. ; et al.
Phys.Rev.D 35 (1987) 2639, 1987.
Inspire Record 215848 DOI 10.17182/hepdata.23381

Data from the High Resolution Spectrometer at the SLAC storage ring PEP have been used to study the inclusive production of baryons and mesons. Time-of-flight measurements are used to identify the charged hadrons. Neutral hadrons are identified from effective-mass peaks associated with their decay into two charged particles. Cross sections and other inclusive production characteristics are presented for π±, K±, and K0 (K¯0) mesons, and for the baryons (antibaryons) p (p¯) and Λ (Λ¯). The ratio of the inclusive cross section to the point cross section for the K0 and K¯0 mesons is R(K0,K¯0)=6.15±0.13±0.25, and for Λ and Λ¯, R(Λ,Λ¯)=0.846±0.036±0.085. The neutral-hadron differential cross sections are compared with the predictions of the Lund string model.

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Study of Quark Fragmentation in e+ e- Annihilation at 29-GeV: Charged Particle Multiplicity and Single Particle Rapidity Distributions

Derrick, M. ; Gan, K.K. ; Kooijman, P. ; et al.
Phys.Rev.D 34 (1986) 3304, 1986.
Inspire Record 18502 DOI 10.17182/hepdata.23443

This paper presents the charged-particle multiplicity distributions for e+e− annihilation at √s =29 GeV measured in the High Resolution Spectrometer. The data, which correspond to an integrated luminosity of 185 pb−1, were obtained at the SLAC e+e− storage ring PEP. The techniques used to correct the observed prong numbers are discussed. The multiplicity distribution of the charged particles has a mean value 〈n〉=12.87±0.03±0.30, a dispersion D2=3.67±0.02±0.18, and an f2 moment of 0.60±0.02±0.18. Results are also presented for a two-jet sample selected with low sphericity and aplanarity. The charged-particle distributions are almost Poissonian and narrower than have been reported by other e+e− experiments in this energy range. The mean multiplicity increases with the event sphericity, and for the sample of threefold-symmetric three-jet events, a value of 〈n〉=16.3±0.3±0.7 is found. No correlation is observed between the multiplicities in the two hemispheres when the events are divided into two jets by a plane perpendicular to the thrust axis. This result is in contrast with the situation in soft hadronic collisions, where a strong forward-backward correlation is measured. For the single jets, a mean multiplicity of 6.43±0.02±0.15 and a dispersion value of D2=2.55±0.02±0.13 are found. These values give further support to the idea of independent jet fragmentation. The multiplicity distributions are well fit by the negative-binomial distribution. The semi-inclusive rapidity distributions are presented. Comparisons are made to the measurements of charged-particle multiplicities in hadron-hadron and lepton-nucleon collisions.

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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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phi MESON PRODUCTION IN e+ e- ANNIHILATIONS AT 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Badtke, D.H. ; et al.
Phys.Rev.Lett. 52 (1984) 2201, 1984.
Inspire Record 200105 DOI 10.17182/hepdata.20445

Production of φ mesons in e+e− annihilation at a center-of-mass energy of 29 GeV has been observed with the time-projection chamber detector at the PEP storage ring. The φ production rate has been measured in the energy range 0.075<x<0.55 (x=2Eφs), giving 0.077±0.012(stat)±0.016(syst) φ's per event. The average value of pt2 relative to the thrust axis is 1.0±0.4 (GeV/c)2.

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CHARGED HADRON INCLUSIVE CROSS-SECTIONS AND FRACTIONS IN e+ e- ANNIHILATION AT S**(1/2) = 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.Lett. 61 (1988) 1263, 1988.
Inspire Record 262143 DOI 10.17182/hepdata.38102

We report measurements of π±K±, and p, p¯ inclusive cross sections and fractions in e+e− annihilation at s=29 GeV, for the momentum interval 0.01<z=ppbeam<0.90. The analysis is based on approximately 70 pb−1 of data collected with the TPC2γ detector facility at the SLAC storage ring PEP. Detector upgrades result in significantly improved momentum coverage and precision of the data, compared to previous measurements.

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Strange Meson Production in $e^+ e^-$ Annihilation

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 47 (1990) 167-180, 1990.
Inspire Record 284251 DOI 10.17182/hepdata.15160

The full TASSO data have been used to study the inclusive production of strange mesons ine+e− annihilations. Differential and total cross sections have been measured in the centre of mass energy range 14 to 44 GeV forK0,\(\bar K^0\) and 34.5 to 44 GeV forK*± (892). We have investigated the strange meson production properties in jets by studying the rapidity andpt2 distributions as well as the evolution of the multiplicities as a function of the event sphericity. We find no evidence that the strange meson yields increase with increasing sphericity faster than the total charged multiplicity.

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Strange Baryon Production in e+ e- Annihilation

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 45 (1989) 209, 1989.
Inspire Record 266893 DOI 10.17182/hepdata.15283

The production of strange baryons ine+e− annihilation has been studied at centre of mass energies of 34.8 GeV and 42.1 GeV, using the TASSO detector at DESY. Inclusive cross-sections have been obtained forΛ0 andΞ− production and an upper limit has been placed upon the production rate of Σ*±(1385). We measure theΛ0 multiplicity per event to be\(\begin{gathered}\hfill \\0.218_{ - 0.011}^{ + 0.011}\pm 0.021 \hfill \\ \end{gathered} \) and\(0.256_{ - 0.029}^{ + 0.030}\pm 0.025\) at\(\sqrt s=34.8\) and 42.1 GeV respectively. The Ξ− multiplicity per event is found to be\(0.014_{ - 0.003}^{ + 0.003}\pm 0.004\) at\(\sqrt s=34.8 GeV\). An investigation has been made of the extent to whichΛ0 are produced in pairs. TheΛ0 cross-section has been studied as a function of event sphericity.

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Charged Multiplicity Distributions and Correlations in e+ e- Annihilation at PETRA Energies

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 45 (1989) 193, 1989.
Inspire Record 277658 DOI 10.17182/hepdata.1499

We report on an analysis of the multiplicity distributions of charged particles produced ine+e− annihilation into hadrons at c.m. energies between 14 and 46.8 GeV. The charged multiplicity distributions of the whole event and single hemisphere deviate significantly from the Poisson distribution but follow approximate KNO scaling. We have also studied the multiplicity distributions in various rapidity intervals and found that they can be well described by the negative binomial distribution only for small central intervals. We have also analysed forward-backward multiplicity correlations for different energies and selections of particle charge and shown that they can be understood in terms of the fragmentation properties of the different quark flavours and by the production and decay of resonances. These correlations are well reproduced by the Lund string model.

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A Study of Energy-energy Correlations Between 12-{GeV} and 46.8-{GeV} {CM} Energies

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 36 (1987) 349-361, 1987.
Inspire Record 248660 DOI 10.17182/hepdata.1698

We present data on energy-energy correlations (EEC) and their related asymmetry (AEEC) ine+e− annihilation in the centre of mass energy range 12<W≦46.8 GeV. The energy and angular dependence of the EEC in the central region is well described byOαs2 QCD plus a fragmentation term proportional to\({1 \mathord{\left/ {\vphantom {1 {\sqrt s }}} \right. \kern-\nulldelimiterspace} {\sqrt s }}\). BareO(α)s2 QCD reproduces our data for the large angle region of the AEEC. Nonperturbative effects for the latter are estimated with the help of fragmentation models. From various analyses using different approximations, we find that values for\(\Lambda _{\overline {MS} } \) in the range 0.1–0.3 GeV give a good description of the data. We also compare analytical calculations in QCD for the EEC in the back-to-back region to our data. The theoretical predictions describe well both the angular and energy dependence of the data in the back-to-back region.

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Pion, Kaon and Proton Cross-sections in $e^+ e^-$ Annihilation at 34-{GeV} and 44-{GeV} Center-of-mass Energy

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 42 (1989) 189, 1989.
Inspire Record 267755 DOI 10.17182/hepdata.1500

The inclusive production of π± andK± mesons and of protons and antiprotons ine+e− annihilations has been measured at 34 GeV and 44 G

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Jet Fragmentation and {QCD} Models in $e^+ e^-$ Annihilation at $c$.m. Energies Between 12-{GeV} and 41.5-{GeV}

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 41 (1988) 359-373, 1988.
Inspire Record 263859 DOI 10.17182/hepdata.15531

The large amount of data accumulated by the TASSO detector at 35 GeV c.m. energy has been compared with the predictions of the latest generation of perturbative QCD+fragmentation models. By adjustment of the arbitrary parameters of these models, a very good description of the global properties of hadronic events was obtained. No one model gave the best description of all features of the data, each model being better than the others for some observables and worse in other quantities. We interpret these results in terms of the underlying QCD and hadronisation schemes. The trends of the data across the energy range 12.0≦W≦41.5 GeV are generally well reproduced by the models with the parameters optimised at 35 GeV.

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Production and Decay of Charmed Mesons in $e^+ e^-$ Annihilation at $\sqrt{s}$ > 28-{GeV}

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 44 (1989) 365, 1989.
Inspire Record 278856 DOI 10.17182/hepdata.15361

We report on a study of inclusive production ofD*± mesons ine+e− annihilation at c.m. energies between 28 and 46.8 GeV using the TASSO detector at the PETRA storage ring. A hardD*± energy spectrum is measured with a maximum nearED*±≃0.6Ebeam. The measured cross section ratio\((\sigma _{D^{* + } }+ \sigma _{D^{* - } } )/\sigma _{\mu \mu }= 1.28 \pm 0.09 \pm 0.18\) indicates thatD* production accounts for a large fraction of the observed charm production. Two complementary methods have been used to determine the forward-backward asymmetry of charm pair production due to electroweak interference. Combining both measurements the product of the axial vector couplings of the electron and the charm quark to the weak neutral current was determined to begAegAc=−(0.276±0.073), in agreement with the standard model prediction of −0.25. Using a sample of reconstructedD*± mesons, the relative strength of the strong interaction coupling of thec quark compared to that of an average of all flavours is measured as αs(c)/αs(all)=0.91±0.38±0.15, consistent with the coupling constant being flavour independent. An update of ourD0 lifetime measurement is presented, based on a considerable increase in statistics, the final result being\(\tau _{D^0= } (4.8 \pm _{0.9 - 0.7}^{1.0 + 0.5} )10^{ - 13} s\).

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Inclusive $\pi^0$ Production by $e^+ e^-$ Annihilation at 34.6-{GeV} Center-of-mass Energy

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 33 (1986) 13, 1986.
Inspire Record 230950 DOI 10.17182/hepdata.45205

The cross section for the processe+e−→π0+ anything has been measured at an average center of mass energy of 34.6 GeV for π0 energies between 0.7 and 17 GeV. The angular distribution for π0 energies larger than 2 GeV is of the formdσ/dΩ∼1+Acos2θ, withA=1.2±0.5. The ratio of π0 to π± production in the measured energy range is 2σ(π0)/(σ(π+)+σ(π−))=1.13±0.18

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Global Jet Properties at 14-{GeV} to 44-{GeV} Center-of-mass Energy in $e^+ e^-$ Annihilation

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 47 (1990) 187-198, 1990.
Inspire Record 294755 DOI 10.17182/hepdata.45170

Jet properties ine+e− annihilation at center of mass energies of 14, 22, 35 and 43.7 GeV were studied with the data collected in the TASSO detector at PETRA, using the same evaluation procedures for all the energies. The total hadronic cross section ratio for the center of mass energy interval 39–47 GeV was determined to be ℛ=4.11±0.05 (stat)±0.18(syst.) at\(\langle \sqrt s \rangle= 43 - 7\) GeV. Corrected distributions of global shape variables are presented as well as the inclusive charged particle distributions for scaled momentum and transverse momentum. The center of mass energy evolution of the average sphericity, thrust, aplanarity and particle momentum is shown.

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Precision Study of $\eta^\prime\rightarrow\gamma\pi^+\pi^-$ Decay Dynamics

The BESIII collaboration Ablikim, M. ; Achasov, M. N. ; Ahmed, S. ; et al.
Phys.Rev.Lett. 120 (2018) 242003, 2018.
Inspire Record 1641075 DOI 10.17182/hepdata.89872

Using a low background data sample of $9.7\times10^{5}$ $J\psi\rightarrow\gamma\eta^\prime$, $\eta^\prime\rightarrow\gamma\pi^+\pi^-$ events, which are 2 orders of magnitude larger than those from the previous experiments, recorded with the BESIII detector at BEPCII, the decay dynamics of $\eta^\prime\rightarrow\gamma\pi^+\pi^-$ are studied with both model-dependent and model-independent approaches. The contributions of $\omega$ and the $\rho(770)-\omega$ interference are observed for the first time in the decays $\eta^\prime\rightarrow\gamma\pi^+\pi^-$ in both approaches. Additionally, a contribution from the box anomaly or the $\rho(1450)$ resonance is required in the model-dependent approach, while the process specific part of the decay amplitude is determined in the model-independent approach.

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INCLUSIVE gamma AND pi0 PRODUCTION CROSS-SECTIONS AND ENERGY FRACTIONS IN e+ e- ANNIHILATION AT 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Bakken, J.A. ; et al.
Z.Phys.C 27 (1985) 187, 1985.
Inspire Record 205868 DOI 10.17182/hepdata.16101

Inclusive production cross sections for photons and π0's ine+e− annihilation at a center of mass energy of 29 GeV have been measured. The π0 production spectrum agrees with a corresponding measurement for π±. The ratio of the π0 inclusive rate to the average for π± is 0.92±0.14. The fractions of the total energy carried by photons and π0's are 0.244±0.016 and 0.217±0.033, respectively. The fraction of total energy carried by all stable hadrons, prompt leptons and photons is determined to be 0.938±0.045, leaving 0.062±0.045 for neutrinos.

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Observation of a Resonance at 4.4-GeV and Additional Structure Near 4.1-GeV in e+ e- Annihilation

Siegrist, J. ; Abrams, G.S. ; Boyarski, A. ; et al.
Phys.Rev.Lett. 36 (1976) 700, 1976.
Inspire Record 108144 DOI 10.17182/hepdata.21093

We observe a resonancelike structure in the total cross section for hadron production by e+e− colliding beams at a mass of 4414 ± 7 MeV having a total width Γ=33±10 MeV. From the area under this resonance, we deduce the partial width to electron pairs to be Γee=440±140 eV. Further structure of comparable width is present near 4.1 GeV.

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Hadron Production by e+ e- Annihilation at Center-Of-Mass Energies Between 2.6-GeV and 7.8-GeV. Part 1. Total Cross-Section, Multiplicities and Inclusive Momentum Distributions

Siegrist, J. ; Schwitters, R. ; Alam, M.S. ; et al.
Phys.Rev.D 26 (1982) 969, 1982.
Inspire Record 169326 DOI 10.17182/hepdata.23889

Measurements of multihadron production in e+e− annihilation at center-of-mass energies between 2.6 and 7.8 GeV are presented. Aside from the narrow resonances ψ(3095) and ψ(3684), the total hadronic cross section is found to be approximately 2.7 times the cross section for the production of muon pairs at c.m. energies below 3.7 GeV and 4.3 times the muon-pair cross section at c.m. energies above 5.5 GeV. Complicated structure is found at intermediate energies. Charged-particle multiplicities and inclusive momentum distributions are presented.

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Production of $\eta$ Mesons in $e^+ e^-$ Annihilations at $\sqrt{s}=29$-{GeV}

The HRS collaboration Abachi, S. ; Akerlof, C. ; Baringer, P. ; et al.
Phys.Lett.B 205 (1988) 111-114, 1988.
Inspire Record 250824 DOI 10.17182/hepdata.29979

Data from e + e − annihilations at 29 GeV have been used to measure the production cross section and fragmentation function of η mesons. The signal is observed in the η → γγ decay channel. The fragmentation for p η >1.5 GeV/ c agrees well with the prediction of the Lund model, whereas the prediction of the Webber model lies above the data. The mean multiplicity is measured to be 〈 n η 〉=0.58±0.10 η mesons per hadronic event, of which 0.51 represents the direct production of η and η ′ mesons in the fragmentation chain.

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Measurement of the Spin Density Matrix of $D^*$ Mesons Produced in $e^+ e^-$ Annihilations

The HRS collaboration Abachi, S. ; Akerlof, C. ; Baringer, P. ; et al.
Phys.Lett.B 199 (1987) 585-590, 1987.
Inspire Record 250823 DOI 10.17182/hepdata.30012

Vector mesons produced in the reaction e + e − →V+X at √ s =29 GeV were isolated by observing D ∗ mesons through the D ∗+ → D 0 π + decay. The D 0 decay modes used are D 0 →K3 π , K π , K π , and K π ( π 0 ). The data, which correspond to an integrated luminosity of 300 pb −1 , were collected by the High Resolution Spectrometer at PEP. Spin density matrix elements for the D ∗ meson are measured as a function of the energy sharing variable Z D ∗ . There is no evidence for alignment of D ∗ mesons produced in e + e − annihilation at our energy.

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Measurement of the $\phi^*_\eta$ distribution of muon pairs with masses between 30 and 500 GeV in 10.4 fb$^{-1}$ of $p\bar{p}$ collisions

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Acharya, Bannanje Sripath ; et al.
Phys.Rev.D 91 (2015) 072002, 2015.
Inspire Record 1324946 DOI 10.17182/hepdata.72484

We present a measurement of the distribution of the variable $\phi^*_\eta$ for muon pairs with masses between 30 and 500 GeV, using the complete Run II data set collected by the D0 detector at the Fermilab Tevatron proton-antiproton collider. This corresponds to an integrated luminosity of 10.4 fb$^{-1}$ at $\sqrt{s}$ = 1.96 TeV. The data are corrected for detector effects and presented in bins of dimuon rapidity and mass. The variable $\phi^*_\eta$ probes the same physical effects as the $Z/\gamma^*$ boson transverse momentum, but is less susceptible to the effects of experimental resolution and efficiency. These are the first measurements at any collider of the $\phi^*_\eta$ distributions for dilepton masses away from the $Z\rightarrow \ell^+\ell^-$ boson mass peak. The data are compared to QCD predictions based on the resummation of multiple soft gluons.

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Measurement of $Z / \gamma^\ast +jet+X$ angular distributions in $p \bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Abolins, Maris A. ; et al.
Phys.Lett.B 682 (2010) 370-380, 2010.
Inspire Record 826756 DOI 10.17182/hepdata.52513

We present the first measurements at a hadron collider of differential cross sections for Z+jet+X production in delta phi(Z, jet), |delta y(Z, jet)| and |y_boost(Z, jet)|. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative QCD and current event generators, which have varied success in describing the data. Using these measurements as inputs in tuning event generators will increase the experimental sensitivity to rare signals.

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Hadron Production in $e^+ e^-$ Annihilation From $\sqrt{s}=5$-{GeV} to 7.4-{GeV}

Edwards, C. ; Partridge, Richard ; Peck, C. ; et al.
SLAC-PUB-5160, 1990.
Inspire Record 294419 DOI 10.17182/hepdata.18758

None

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Measurements of Total Hadronic and Inclusive $D^*$ Cross-sections in $e^+ e^-$ Annihilations Between 3.87-{GeV} and 4.5-{GeV}

Osterheld, A. ; Hofstadter, R. ; Horisberger, R. ; et al.
SLAC-PUB-4160, 1986.
Inspire Record 238081 DOI 10.17182/hepdata.18759

None

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PION AND KAON MULTIPLICITIES IN HEAVY QUARK JETS FROM e+ e- ANNIHILATION AT 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Lett.B 184 (1987) 299-304, 1987.
Inspire Record 235694 DOI 10.17182/hepdata.30210

The multiplicities per event of π ± and K ± are measured separately for e + e - annihilation into c c , b b , and light quark pairs at E cm=29 GeV. The K ± multiplicity is higher for heavy quark events than for light quark events. The π ± multiplicity and the π ± scaled differential cross section at low x = E beam/ E beam are found to be higher for b b events than for other events.

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Measurement of three-jet differential cross sections d sigma-3jet / d M-3jet in p anti-p collisions at sqrt(s)=1.96 TeV

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Acharya, Bannanje Sripath ; et al.
Phys.Lett.B 704 (2011) 434-441, 2011.
Inspire Record 895662 DOI 10.17182/hepdata.58856

We present the first measurement of the inclusive three-jet differential cross section as a function of the invariant mass of the three jets with the largest transverse momenta in an event in p anti-p collisions at sqrt(s) = 1.96 TeV. The measurement is made in different rapidity regions and for different jet transverse momentum requirements and is based on a data set corresponding to an integrated luminosity of 0.7 fb^{-1} collected with the D0 detector at the Fermilab Tevatron Collider. The results are used to test the three-jet matrix elements in perturbative QCD calculations at next-to-leading order in the strong coupling constant. The data allow discrimination between parametrizations of the parton distribution functions of the proton.

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Measurement of the normalized Z/gamma*->mu+mu- transverse momentum distribution in p\bar{p} collisions at sqrt{s}=1.96 TeV

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Abolins, Maris A. ; et al.
Phys.Lett.B 693 (2010) 522-530, 2010.
Inspire Record 856972 DOI 10.17182/hepdata.55457

We present a new measurement of the Z/gamma* transverse momentum distribution in the range 0 - 330GeV, in proton-antiproton collisions at sqrt{s}=1.96 TeV. The measurement uses 0.97 fb-1 of integrated luminosity recorded by the D0 experiment and is the first using the Z/gamma*->mu+mu- + X channel at this center-of-mass energy. This is also the first measurement of the Z/gamma* transverse momentum distribution that presents the result at the level of particles entering the detector, minimizing dependence on theoretical models. As any momentum of the Z/gamma* in the plane transverse to the incoming beams must be balanced by some recoiling system, primarily the result of QCD radiation in the initial state, this variable is an excellent probe of the underlying process. Tests of the predictions of QCD calculations and current event generators show they have varied success in describing the data. Using this measurement as an input to theoretical predictions will allow for a better description of hadron collider data and hence it will increase experimental sensitivity to rare signals.

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Precise study of the Z/gamma* boson transverse momentum distribution in ppbar collisions using a novel technique

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Abolins, Maris A. ; et al.
Phys.Rev.Lett. 106 (2011) 122001, 2011.
Inspire Record 871787 DOI 10.17182/hepdata.56732

Using 7.3 pb-1 of ppbar collisions collected by the D0 detector at the Fermilab Tevatron, we measure the distribution of the variable \phistar, which probes the same physical effects as the Z/gamma* boson transverse momentum, but is less susceptible to the effects of experimental resolution and efficiency. A QCD prediction is found to describe the general features of the \phistar distribution, but is unable to describe its detailed shape or dependence on boson rapidity. A prediction that includes a broadening of transverse momentum for small values of the parton momentum fraction is strongly disfavored.

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Dimuon production in proton - copper collisions at s**(1/2) = 38.8-GeV

Moreno, G. ; Brown, C.N. ; Cooper, W.E. ; et al.
Phys.Rev.D 43 (1991) 2815-2836, 1991.
Inspire Record 302822 DOI 10.17182/hepdata.22831

Experimental results on the production of dimuons by 800-GeV protons incident on a copper target are presented. The results include measurements of both the continuum of dimuons and the dimuon decays of the three lowest-mass ϒ S states. A description of the apparatus, data acquisition, and analysis techniques is included. A comparison of the results with data taken at lower incident energies indicates a scaling behavior of the continuum dimuon yields.

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Study of the process $e^+e^-\to\eta\gamma$ in the center-of-mass energy range 1.07--2.00 GeV

Achasov, M.N. ; Aulchenko, V.M. ; Barnyakov, A.Yu. ; et al.
Phys.Rev.D 90 (2014) 032002, 2014.
Inspire Record 1275333 DOI 10.17182/hepdata.62279

The $e^+e^-\to\eta\gamma$ cross section has been measured in the center-of-mass energy range 1.07--2.00 GeV using the decay mode $\eta\to 3\pi^0$, $\pi^0\to \gamma\gamma$. The analysis is based on 36 pb$^{-1}$ of integrated luminosity collected with the SND detector at the VEPP-2000 $e^+e^-$ collider. The measured cross section of about 35 pb at 1.5 GeV is explained by decays of the $\rho(1450)$ and $\phi(1680)$ resonances.

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Measurement of the $e^+e^- \to \eta\pi^+\pi^-$ cross section in the center-of-mass energy range 1.22--2.00 GeV with the SND detector at the VEPP-2000 collider

The SND collaboration Aulchenko, V.M. ; Achasov, M.N. ; Barnyakov, A.Yu. ; et al.
Phys.Rev.D 91 (2015) 052013, 2015.
Inspire Record 1332929 DOI 10.17182/hepdata.73176

In the experiment with the SND detector at the VEPP-2000 $e^+e^-$ collider the cross section for the process $e^+e^-\to\eta\pi^+\pi^-$ has been measured in the center-of-mass energy range from 1.22 to 2.00 GeV. Obtained results are in agreement with previous measurements and have better accuracy. The energy dependence of the $e^+e^-\to\eta\pi^+\pi^-$ cross section has been fitted with the vector-meson dominance model. From this fit the product of the branching fractions $B(\rho(1450)\to\eta\pi^+\pi^-)B(\rho(1450)\to e^+e^-)$ has been extracted and compared with the same products for $\rho(1450)\to\omega\pi^0$ and $\rho(1450)\to\pi^+\pi^-$ decays. The obtained cross section data have been also used to test the conservation of vector current hypothesis.

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Study of the process $e^+e^-\to n\bar{n}$ at the VEPP-2000 $e^+e^-$ collider with the SND detector

Achasov, M.N. ; Barnyakov, A.Yu. ; Beloborodov, K.I. ; et al.
Phys.Rev.D 90 (2014) 112007, 2014.
Inspire Record 1321689 DOI 10.17182/hepdata.71416

The process $e^+e^-\to n\bar{n}$ has been studied at the VEPP-2000 $e^+e^-$ collider with the SND detector in the energy range from threshold up to 2 GeV. As a result of the experiment, the $e^+e^-\to n\bar{n}$ cross section and effective neutron form factor have been measured.

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Study of the reaction $e^+e^- \to \pi^0\gamma$ with the SND detector at the VEPP-2M collider

The SND collaboration Achasov, M.N. ; Beloborodov, K.I. ; Berdyugin, A.V. ; et al.
Phys.Rev.D 93 (2016) 092001, 2016.
Inspire Record 1418483 DOI 10.17182/hepdata.77047

The process $e^+e^- \to \pi^0\gamma$ has been studied in the experiment with the SND detector at the VEPP-2M $e^+e^-$ collider. The $e^+e^- \to \pi^0\gamma$ cross section has been measured in the center-of-mass energy range from 0.60 to 1.38 GeV. The cross section is well described by the vector meson dominance model. From the fit to the cross section data we have determined the branching fractions $B(\rho\to\pi^0\gamma)=(4.20\pm0.52)\times10^{-4}$, $B(\omega\to\pi^0\gamma)=(8.88\pm0.18)\%$, $B(\phi\to\pi^0\gamma)=(1.367\pm0.072)\times10^{-3}$, and the relative phase between the $\rho$ and $\omega$ amplitudes $\varphi_{\rho}=(-12.7\pm4.5)^\circ$. Our data on the process $e^+e^- \to \pi^0\gamma$ are the most accurate to date.

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A Study of the Energy Dependence of the Underlying Event in Proton-Antiproton Collisions

The CDF collaboration Aaltonen, Timo Antero ; Amerio, Silvia ; Amidei, Dante E ; et al.
Phys.Rev.D 92 (2015) 092009, 2015.
Inspire Record 1388868 DOI 10.17182/hepdata.70787

We study charged particle production in proton-antiproton collisions at 300 GeV, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of eta-phi space; toward, away, and transverse. The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the underlying event. The transverse region is divided into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event are studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.

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Processes e+ e- --> K+ K-, K(S) K(L) and pi+ pi- pi0 at the Phi(1020) resonance energy region.

Achasov, M.N. ; Beloborodov, K.I. ; Berdyugin, A.V. ; et al.
Phys.Rev.D 63 (2001) 072002, 2001.
Inspire Record 533574 DOI 10.17182/hepdata.41706

The cross sections of the processes $e^+e^- \to K^+K^-$, $e^+e^- \to K_SK_L$ and $e^+e^- \to \pi^+\pi^-\pi^0$ were measured in the SND experiment at the VEPP-2M collider in the energy region near the $\phi(1020)$ meson. These measurements were based on about $10^6$ $K^+K^-$, $0.5 \times 10^6$ $K_SK_L$ and $0.4 \times 10^6$ $\pi^+\pi^-\pi^0$ selected events. Themeasured cross sections have been analyzed in the framework of the vector meson dominance model and the main parameters of the $\phi$-resonance were obtained, such as its mass, width, the production cross section and branching ratios of the main decay modes. The measured value of the $\phi$ meson total width, $\Gamma_{\phi} = 4.21 \pm 0.04$ is lower than the present world average of $4.458 \pm 0.032$ MeV. Contributions in addition to the conventional vector meson dominance model were found in the $e^+e^- \to \pi^+\pi^-\pi^0$ reaction cross section.

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Experimental Study of rho -> pi0 pi0 gamma and omega -> pi0 pi0 gamma Decays

Achasov, M.N. ; Beloborodov, K.I. ; Berdyugin, A.V. ; et al.
Phys.Lett.B 537 (2002) 201-210, 2002.
Inspire Record 587084 DOI 10.17182/hepdata.41973

The e+e- -> pi0 pi0 gamma process was studied in the SND experiment at VEPP-2M e+e- collider in the energy region 0.60-0.97 GeV. From the analysis of the energy dependence of measured cross section the branching ratios B(omega -> pi0 pi0 gamma)= (6.6 +1.4-0.8(stat) +-0.6(syst))x10^-5 and B(rho -> pi0 pi0 gamma)=(4.1 +1.0-0.9(stat) +-0.3(syst))x10^-5 were obtained.

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Measurement of the e+e- -> pi+pi- cross section with the CMD-2 detector in the 370-520 MeV c.m. energy range

Aul'chenko, V.M. ; Akhmetshin, R.R. ; Banzarov, V.Sh. ; et al.
JETP Lett. 84 (2006) 413-417, 2006.
Inspire Record 728191 DOI 10.17182/hepdata.41786

The cross section of the process e+e- -> pi+pi- has been measured at the CMD-2 detector in the 370-520 MeV center-of-mass (c.m.) energy range. A systematic uncertainty of the measurement is 0.7 %. Using all CMD-2 data on the pion form factor, the pion electromagnetic radius was calculated. The cross section of muon pair production was also determined.

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Measurement of $d\sigma/dy$ of Drell-Yan $e^+e^-$ pairs in the $Z$ Mass Region from $p\bar{p}$ Collisions at $\sqrt{s}=1.96$ TeV

The CDF collaboration Aaltonen, Timo Antero ; Adelman, Jahred A. ; Alvarez Gonzalez, Barbara ; et al.
Phys.Lett.B 692 (2010) 232-239, 2010.
Inspire Record 856131 DOI 10.17182/hepdata.52674

We report on a CDF measurement of the total cross section and rapidity distribution, $d\sigma/dy$, for $q\bar{q}\to \gamma^{*}/Z\to e^{+}e^{-}$ events in the $Z$ boson mass region ($66<M_{ee}<116$GeV/c$^2$) produced in $p\bar{p}$ collisions at $\sqrt{s}=1.96$TeV with 2.1fb$^{-1}$ of integrated luminosity. The measured cross section of $257\pm16$pb and $d\sigma/dy$ distribution are compared with Next-to-Leading-Order(NLO) and Next-to-Next-to-Leading-Order(NNLO) QCD theory predictions with CTEQ and MRST/MSTW parton distribution functions (PDFs). There is good agreement between the experimental total cross section and $d\sigma/dy$ measurements with theoretical calculations with the most recent NNLO PDFs.

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Study of the process $e^+e^-\to\omega\eta\pi^0$ in the energy range $\sqrt{s} <2$ GeV with the SND detector

Achasov, M.N. ; Aulchenko, V.M. ; Barnyakov, A.Yu. ; et al.
Phys.Rev.D 94 (2016) 032010, 2016.
Inspire Record 1471515 DOI 10.17182/hepdata.82577

The process $e^+e^-\to\omega\eta\pi^0$ is studied in the energy range $1.45-2.00$ GeV using data with an integrated luminosity of 33 pb$^{-1}$ accumulated by the SND detector at the $e^+e^-$ collider VEPP-2000. The $e^+e^-\to\omega\eta\pi^0$ cross section is measured for the first time. The cross section has a threshold near 1.75 GeV. Its value is about 2 nb in the energy range $1.8-2.0$ GeV. The dominant intermediate state for the process $e^+e^- \to \omega\eta\pi^0$ is found to be $\omega a_0(980)$.

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