Single $\pi^0$ Production Off Neutrons Bound in Deuteron with Linearly Polarized Photons

The A2 at MAMI collaboration Mullen, C. ; Gardner, S. ; Glazier, D.I. ; et al.
Eur.Phys.J.A 57 (2021) 205, 2021.
Inspire Record 1851649 DOI 10.17182/hepdata.127968

The quasifree $\overrightarrow{\gamma} d\to\pi^0n(p)$ photon beam asymmetry, $\Sigma$, has been measured at photon energies, $E_\gamma$, from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49 to 148$^\circ$. In this kinematic region, polarization observables are sensitive to contributions from the $\Delta (1232)$ and $N(1440)$ resonances. The extracted values of $\Sigma$ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID, and Bonn-Gatchina analyses; while a revised SAID fit, including the new $\Sigma$ measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict $\pi^0n$ photoproduction observables, based on fits to published data in the channels $\pi^0p$, $\pi^+n$, and $\pi^-p$.

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Photon beam asymmetry Sigma at W= 1.2711 GeV

Photon beam asymmetry Sigma at W= 1.2858 GeV

Photon beam asymmetry Sigma at W= 1.3003 GeV

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Measurement of the Muon Charge Asymmetry in Inclusive $pp \to W+X$ Production at $\sqrt s =$ 7 TeV and an Improved Determination of Light Parton Distribution Functions

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Phys.Rev.D 90 (2014) 032004, 2014.
Inspire Record 1273570 DOI 10.17182/hepdata.65456

Measurements of the muon charge asymmetry in inclusive pp to WX production at sqrt(s) = 7 TeV are presented. The data sample corresponds to an integrated luminosity of 4.7 inverse femtobarns recorded with the CMS detector at the LHC. With a sample of more than twenty million W to mu nu events, the statistical precision is greatly improved in comparison to previous measurements. These new results provide additional constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable x from 10E-3 to 10E-1. These measurements and the recent CMS measurement of associated W + charm production are used together with the cross sections for inclusive deep inelastic ep scattering at HERA in a next-to-leading-order QCD analysis. The determination of the valence quark distributions is improved, and the strange-quark distribution is probed directly through the leading-order process g + s to W + c in proton-proton collisions at the LHC.

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Summary of the final results for muon charge asymmetry $\mathcal{A}$ with the muon $p_{T}>25$ GeV. The first uncertainty is statistical and the second is systematic. The theoretical predictions are obtained using the FEWZ 3.1 MC tool interfaced with the NLO CT10, NNPDF2.3, HERAPDF1.5, and MSTW2008CPdeut PDF sets. The PDF uncertainty is at 68% C.L. The values are expressed as percentages.

Summary of the final results for muon charge asymmetry $\mathcal{A}$ with the muon $p_{T}>35$ GeV. The first uncertainty is statistical and the second is systematic. The theoretical predictions are obtained using the FEWZ 3.1 MC tool interfaced with the NLO CT10, NNPDF2.3, HERAPDF1.5, and MSTW2008CPdeut PDF sets. The PDF uncertainty is at 68% C.L. The values are expressed as percentages.

Covariance matrix (statistical and systematic uncertainties combined) with the muon $p_{T}>25$ GeV. The units are in $10^{-4}$.

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Measurement of Parity-Violating Asymmetry in Electron-Deuteron Inelastic Scattering

Wang, D. ; Pan, K. ; Subedi, R. ; et al.
Phys.Rev.C 91 (2015) 045506, 2015.
Inspire Record 1327482 DOI 10.17182/hepdata.72848

The parity-violating asymmetries between a longitudinally-polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were published earlier, but are presented here in more detail.

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Asymmetry results on $\vec e-^2$H parity-violating scattering from the PVDIS experiment at JLab.

Asymmetry results on $\vec e-^2$H parity-violating scattering from the PVDIS experiment at JLab, for RES I settings.

Asymmetry results on $\vec e-^2$H parity-violating scattering from the PVDIS experiment at JLab, for RES II settings.

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Net-Charge Fluctuations in Pb-Pb collisions at \surds_NN = 2.76 TeV

The ALICE collaboration Abelev, Betty ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.Lett. 110 (2013) 152301, 2013.
Inspire Record 1123802 DOI 10.17182/hepdata.60476

We report the first measurement of the net-charge fluctuations in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV, measured with the ALICE detector at the CERN Large Hadron Collider. The dynamical fluctuations per unit entropy are observed to decrease when going from peripheral to central collisions. An additional reduction in the amount of fluctuations is seen in comparison to the results from lower energies. We examine the dependence of fluctuations on the pseudorapidity interval, which may account for the dilution of fluctuations during the evolution of the system. We find that the fluctuations at LHC are smaller compared to the measurements at the Relativistic heavy Ion Collider (RHIC), and as such, closer to what has been theoretically predicted for the formation of Quark-Gluon Plasma (QGP).

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The measured NU(+-DYN) as a function of the centrality of the collisions, expressed as the number of participating nucleons, for two values of midrapidity range.

NU(+-DYN), corrected for charge conservation and finite acceptance effects, as a function of the centrality of the collisions, expressed as the number of participating nucleons, for two values of midrapidity range.

The measured and corrected NU(+-DYN) in P P collisions for two values of midrapidity range.

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Higher-Order Cumulants and Correlation Functions of Proton Multiplicity Distributions in $\sqrt{s_{\mathrm{NN}}}$ = 3 GeV Au+Au Collisions at the STAR Experiment

The STAR collaboration Abdallah, Mohamed ; Aboona, Bassam ; Adam, Jaroslav ; et al.
Phys.Rev.C 107 (2023) 024908, 2023.
Inspire Record 2631860 DOI 10.17182/hepdata.134023

We report a measurement of cumulants and correlation functions of event-by-event proton multiplicity distributions from fixed-target Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 3 GeV measured by the STAR experiment. Protons are identified within the rapidity ($y$) and transverse momentum ($p_{\rm T}$) region $-0.9 < y<0$ and $0.4 < p_{\rm T} <2.0 $ GeV/$c$ in the center-of-mass frame. A systematic analysis of the proton cumulants and correlation functions up to sixth-order as well as the corresponding ratios as a function of the collision centrality, $p_{\rm T}$, and $y$ are presented. The effect of pileup and initial volume fluctuations on these observables and the respective corrections are discussed in detail. The results are compared to calculations from the hadronic transport UrQMD model as well as a hydrodynamic model. In the most central 5% collisions, the value of proton cumulant ratio $C_4/C_2$ is negative, drastically different from the values observed in Au+Au collisions at higher energies. Compared to model calculations including Lattice QCD, a hadronic transport model, and a hydrodynamic model, the strong suppression in the ratio of $C_4/C_2$ at 3 GeV Au+Au collisions indicates an energy regime dominated by hadronic interactions.

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The uncorrected number of charged particles except protons ($N_{\rm ch}$) within the pseudorapidity $−2<\eta<0$ used for the centrality selection for Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 3 GeV. The centrality classes are expressed in % of the total cross section. The lower boundary of the particle multiplicity ($N_{\rm ch}$) is included for each centrality class. Values are provided for the average number of participants ($\langle N_{\rm part}\rangle$) and pileup fraction. The fraction of pileup for each centrality bin is also shown in the last column. The averaged pileup fraction from the minimum biased collisions is determined to be 0.46%. Values in the parentheses are systematic uncertainty.

The centrality definition determined by $N_{\rm part}$ in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 3 GeV from the UrQMD model. The centrality definition is only used in the UrQMD calculation.

Main contributors to systematic uncertainty to the proton cumulant ratios: $C_2/C_1$, $C_3/C_2$,and $C_4/C_2$ from 0–5% central 3 GeV Au+Au collisions. The first row shows the values and statistical uncertainties of those ratios. The corresponding values of these ratios along with the statistical uncertainties are listed in the table. The final total value is the quadratic sum of uncertainties from centrality, pileup, and the dominant contribution from TPC hits, DCA, TOF $m^2$, and detector efficiency. Clearly, this analysis is systematically dominant.

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Constraining the Higgs boson self-coupling from single- and double-Higgs production with the ATLAS detector using $pp$ collisions at $\sqrt{s}=13$ TeV

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
Phys.Lett.B 843 (2023) 137745, 2023.
Inspire Record 2175556 DOI 10.17182/hepdata.135471

Constraints on the Higgs boson self-coupling are set by combining double-Higgs boson analyses in the $b\bar{b}b\bar{b}$, $b\bar{b}\tau^+\tau^-$ and $b\bar{b} \gamma \gamma$ decay channels with single-Higgs boson analyses targeting the $\gamma \gamma$, $ZZ^*$, $WW^*$, $\tau^+ \tau^-$ and $b\bar{b}$ decay channels. The data used in these analyses were recorded by the ATLAS detector at the LHC in proton$-$proton collisions at $\sqrt{s}=13$ TeV and correspond to an integrated luminosity of 126$-$139 fb$^{-1}$. The combination of the double-Higgs analyses sets an upper limit of $\mu_{HH} < 2.4$ at 95% confidence level on the double-Higgs production cross-section normalised to its Standard Model prediction. Combining the single-Higgs and double-Higgs analyses, with the assumption that new physics affects only the Higgs boson self-coupling ($\lambda_{HHH}$), values outside the interval $-0.4< \kappa_{\lambda}=(\lambda_{HHH}/\lambda_{HHH}^{\textrm{SM}})< 6.3$ are excluded at 95% confidence level. The combined single-Higgs and double-Higgs analyses provide results with fewer assumptions, by adding in the fit more coupling modifiers introduced to account for the Higgs boson interactions with the other Standard Model particles. In this relaxed scenario, the constraint becomes $-1.4 < \kappa_{\lambda} < 6.1$ at 95% CL.

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Observed and expected 95% CL upper limits on the signal strength for double-Higgs production from the bbbb, bb$\tau\tau$ and bb$\gamma\gamma$ decay channels, and their statistical combination. The value $m_H$ = 125.09 GeV is assumed when deriving the predicted SM cross-section. The expected limit and the corresponding error bands are derived assuming the absence of the HH process and with all nuisance parameters profiled to the observed data.

Observed and expected 95% CL exclusion limits on the production cross-sections of the combined ggF HH and VBF HH processes as a function of $\kappa_\lambda$, for the three double-Higgs search channels and their combination. The expected limits assume no HH production. The red line shows the theory prediction for the combined ggF HH and VBF HH cross-section as a function of $\kappa_\lambda$ where all parameters and couplings are set to their SM values except for $\kappa_\lambda$. The band surrounding the red cross-section lines indicate the theoretical uncertainty of the predicted cross-section.

Observed and expected 95% CL exclusion limits on the production cross-sections of the VBF HH process as a function of $\kappa_{2V}$, for the three double-Higgs search channels and their combination. The expected limits assume no VBF HH production. The red line shows the predicted VBF HH cross-section as a function of $\kappa_{2V}$. The bands surrounding the red cross-section lines indicate the theoretical uncertainty of the predicted cross-section. The uncertainty band is smaller than the width of the plotted line.

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Study of $\eta$ and $\eta'$ photoproduction at MAMI

The A2 collaboration Kashevarov, V.L. ; Ott, P. ; Prakhov, S. ; et al.
Phys.Rev.Lett. 118 (2017) 212001, 2017.
Inspire Record 1509373 DOI 10.17182/hepdata.116258

The reactions $\gamma p\to \eta p$ and $\gamma p\to \eta' p$ have been measured from their thresholds up to the center-of-mass energy $W=1.96$GeV with the tagged-photon facilities at the Mainz Microtron, MAMI. Differential cross sections were obtained with unprecedented accuracy, providing fine energy binning and full production-angle coverage. A strong cusp is observed in the total cross section and excitation functions for $\eta$ photoproduction at the energies in vicinity of the $\eta'$ threshold, $W=1896$MeV ($E_\gamma=1447$MeV). This behavior is explained in a revised $\eta$MAID isobar model by a significant branching of the $N(1895)1/2^-$ nucleon resonance to both, $\eta p$ and $\eta' p$, confirming the existence and constraining the properties of this poorly known state.

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Run 1. Total cross section as a function of c.m. energy W.

Run 2. Total cross section as a function of c.m. energy W.

Run 3. Total cross section as a function of c.m. energy W.

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Cross Section for $\gamma n \to \pi^0 n$ measured at Mainz/A2

The A2 collaboration Briscoe, W.J. ; Hadžimehmedović, M. ; Kudryavtsev, A.E. ; et al.
Phys.Rev.C 100 (2019) 065205, 2019.
Inspire Record 1748263 DOI 10.17182/hepdata.116236

The $\gamma n \to \pi^0 n$ differential cross section evaluated for 27 energy bins span the photon-energy range 290-813 MeV (W = 1.195-1.553 GeV) and the pion c.m. polar production angles, ranging from 18 deg to 162 deg, making use of model-dependent nuclear corrections to extract pi0 production data on the neutron from measurements on the deuteron target. Additionally, the total photoabsorption cross section was measured. The tagged photon beam produced by the 883-MeV electron beam of the Mainz Microtron MAMI was used for the 0-meson production. Our accumulation of 3.6 x 10^6 $\gamma n \to \pi^0 n$ events allowed a detailed study of the reaction dynamics. Our data are in reasonable agreement with previous A2 measurements and extend them to lower energies. The data are compared to predictions of previous SAID, MAID, and BnGa partial-wave analyses and to the latest SAID fit MA19 that included our data. Selected photon decay amplitudes $N^* \to \gamma n$ at the resonance poles are determined for the first time.

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Excitation function at pion c.m. angle THETA=18 deg as function of incident photon energy E. The uncertainties are statistical and systematic, combined in quadrature.

Excitation function at pion c.m. angle THETA=32 deg as function of incident photon energy E. The uncertainties are statistical and systematic, combined in quadrature.

Excitation function at pion c.m. angle THETA=41 deg as function of incident photon energy E. The uncertainties are statistical and systematic, combined in quadrature.

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Inclusive $\K^0$(s), $\Lambda$ and Anti-lambda Production in $\pi^+ D$ Interactions at 24-{GeV}/c

Dado, S. ; Goldberg, J. ; Toaff, S. ; et al.
Phys.Rev.D 22 (1980) 2656, 1980.
Inspire Record 8878 DOI 10.17182/hepdata.4164

We have studied inclusive KS0, Λ, and Λ¯ production in π+d interactions at 24 GeV/c. The observed cross sections are 2.5±0.13 mb for KS0, 1.62±0.09 mb for Λ, and 0.12±0.02 mb for Λ¯. Longitudinal- and transverse-momentum distributions of the produced particles are presented. The average charged multiplicities of the system associated with a KS0 or with a Λ are presented and discussed. A nonzero average Λ polarization (-0.10±0.03) is observed. The x distribution of the backward (forward) KS0 and Λ produced in the reaction are in agreement with the x distribution of valence quarks in nucleons in nuclear target (pion beam), as predicted by the quark-recombination model of particle production applied to nuclear targets.

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Axis error includes +- 0.0/0.0 contribution (?////THE QUOTED IN THE TABLES ERROR INCLUDE ESTIMATES OF UNCERTAINTY IN EACH OF THE CORRECTIONS MADE IN ADDITION TO THE STATISTICAL ERRORCORRECTIONS HAVE BEEN MADE FOR DETECTION, MEASURING, AND FITTING LOSSES AS WELL AS FOR NEUTRAL DECAY MODES OF THE STRANGE PARTICLESNO CORRECTION WAS MADE FOR CONTAMINATION FROM KL'S NOR FOR UNAVOIDABLE INCLUSION OF SIGMA0 EVENTS).

Axis error includes +- 0.0/0.0 contribution (?////THE QUOTED IN THE TABLES ERROR INCLUDE ESTIMATES OF UNCERTAINTY IN EACH OF THE CORRECTIONS MADE IN ADDITION TO THE STATISTICAL ERRORCORRECTIONS HAVE BEEN MADE FOR DETECTION, MEASURING, AND FITTING LOSSES AS WELL AS FOR NEUTRAL DECAY MODES OF THE STRANGE PARTICLESNO CORRECTION WAS MADE FOR CONTAMINATION FROM KL'S NOR FOR UNAVOIDABLE INCLUSION OF SIGMA0 EVENTS).

Axis error includes +- 0.0/0.0 contribution (?////THE QUOTED IN THE TABLES ERROR INCLUDE ESTIMATES OF UNCERTAINTY IN EACH OF THE CORRECTIONS MADE IN ADDITION TO THE STATISTICAL ERRORCORRECTIONS HAVE BEEN MADE FOR DETECTION, MEASURING, AND FITTING LOSSES AS WELL AS FOR NEUTRAL DECAY MODES OF THE STRANGE PARTICLESNO CORRECTION WAS MADE FOR CONTAMINATION FROM KL'S NOR FOR UNAVOIDABLE INCLUSION OF SIGMA0 EVENTS).

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Hyperon Production in $e^+ e^-$ Interactions in the $\Upsilon$ Region

The CLEO collaboration Alam, M.S. ; Csorna, S.E. ; Garren, L. ; et al.
Phys.Rev.Lett. 53 (1984) 24, 1984.
Inspire Record 200712 DOI 10.17182/hepdata.20410

We report measurements from the CLEO detector of the rate of Ξ and Λ production in e+e− interactions in the upsilon region. Hyperon production from the decay of the ϒ(1s) is compared with continuum e+e− data. The ratio of the production rates of Λ (and Λ―) to K0 (and K―0) on the ϒ(1s) is 0.21 ± 0.03, much larger than in the continuum, 0.07 ± 0.01. The ratios of the production rates of the Ξ and Λ are comparable, 0.10±0.02 [ϒ(1S)] and 0.07 ± 0.02 (continuum). We discuss some implications of the data for gluon and quark fragmentation models.

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CONTINUUM IS ECM 10.38 TO 10.64 GEV.

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