A Study of the Inclusive $K_s^0$, $\Lambda$, $\bar{\Lambda}$ Production in Diffractive $\gamma$P Interactions

Bhadra, S. ; Appel, J.A. ; Bartlett, D.F. ; et al.
Phys.Rev.Lett. 55 (1985) 2749, 1985.
Inspire Record 217669 DOI 10.17182/hepdata.20275

We have studied inclusive KS, Λ, and Λ¯ photoproduction over the ranges 40<Eγ<170 GeV and forward produced mass 2<MF<10 GeV. We observe equal Λ and Λ¯ production rates and spectra as expected in a diffractive process where the target proton remains unaltered. We show that the fraction of hadronic events with a strange particle produced in events with forward mass MF agrees well with the same measurement in e+e− annihilation at a center-of-mass energy Ec.m.=MF. The x=2PMF distributions of these three particles in the forward-mass rest frame are compared with theoretical predictions.

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$\tau$ Leptonic Branching Ratios and a Search for Goldstone Decay

The MARK-III collaboration Baltrusaitis, R.M. ; Becker, J. ; Blaylock, G. ; et al.
Phys.Rev.Lett. 55 (1985) 1842, 1985.
Inspire Record 215995 DOI 10.17182/hepdata.20284

Pairs of τ leptons produced at s=3.77 GeV have been studied in eμ, ee, and μμ final states. The leptonic branching ratios have been measured to be B(τ→eνν)=(18.2±0.7±0.5)% and B(τ→μνν)=(18.0±1.0±0.6)%. Limits have been set for the two-body decays τ→eG and τ→μG, where G is a light Goldstone boson.

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Measurement of Charged Pion Production Yields off the NuMI Target

The MIPP collaboration Paley, J.M. ; Messier, M.D. ; Raja, R. ; et al.
Phys.Rev.D 90 (2014) 032001, 2014.
Inspire Record 1291947 DOI 10.17182/hepdata.64417

The fixed-target MIPP experiment, Fermilab E907, was designed to measure the production of hadrons from the collisions of hadrons of momenta ranging from 5 to 120 GeV/c on a variety of nuclei. These data will generally improve the simulation of particle detectors and predictions of particle beam fluxes at accelerators. The spectrometer momentum resolution is between 3 and 4%, and particle identification is performed for particles ranging between 0.3 and 80 GeV/c using $dE/dx$, time-of-flight and Cherenkov radiation measurements. MIPP collected $1.42 \times10^6$ events of 120 GeV Main Injector protons striking a target used in the NuMI facility at Fermilab. The data have been analyzed and we present here charged pion yields per proton-on-target determined in bins of longitudinal and transverse momentum between 0.5 and 80 GeV/c, with combined statistical and systematic relative uncertainties between 5 and 10%.

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The production yields of PI+ and PI- and the ratio of these yields. The first uncertainty given on each value combines statistical uncertainties and systematic uncertainties from backgrounds.


Study of the $e^+e^-\to K^+K^-$ reaction in the energy range from 2.6 to 8.0 GeV

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Tisserand, V. ; et al.
Phys.Rev.D 92 (2015) 072008, 2015.
Inspire Record 1383130 DOI 10.17182/hepdata.73784

The $e^+e^-\to K^+K^-$ cross section and charged-kaon electromagnetic form factor are measured in the $e^+e^-$ center-of-mass energy range ($E$) from 2.6 to 8.0 GeV using the initial-state radiation technique with an undetected photon. The study is performed using 469 fb$^{-1}$ of data collected with the BABAR detector at the PEP-II $e^+e^-$ collider at center-of-mass energies near 10.6 GeV. The form factor is found to decrease with energy faster than $1/E^2$, and approaches the asymptotic QCD prediction. Production of the $K^+K^-$ final state through the $J/\psi$ and $\psi(2S)$ intermediate states is observed. The results for the kaon form factor are used together with data from other experiments to perform a model-independent determination of the relative phases between single-photon and strong amplitudes in $J/\psi$ and $\psi(2S)\to K^+K^-$ decays. The values of the branching fractions measured in the reaction $e^+e^- \to K^+K^-$ are shifted relative to their true values due to interference between resonant and nonresonant amplitudes. The values of these shifts are determined to be about $\pm5\%$ for the $J/\psi$ meson and $\pm15\%$ for the $\psi(2S)$ meson.

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The $K^+K^-$ invariant-mass interval ($M_{K^+K^-}$), number of selected events ($N_{\rm sig}$) after background subtraction, detection efficiency ($\varepsilon$), ISR luminosity ($L$), measured $e^+e^-\to K^+K^-$ cross section ($\sigma_{K^+K^-}$), and the charged-kaon form factor ($|F_K|$). For the number of events and cross section. For the form factor, we quote the combined uncertainty. For the mass interval 7.5 - 8.0 GeV/$c^2$, the 90$\%$ CL upper limits for the cross section and form factor are listed.


Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 114 (2015) 252302, 2015.
Inspire Record 1358666 DOI 10.17182/hepdata.72237

We present measurements of $\pi^-$ and $\pi^+$ elliptic flow, $v_2$, at midrapidity in Au+Au collisions at $\sqrt{s_{_{\rm NN}}} =$ 200, 62.4, 39, 27, 19.6, 11.5 and 7.7 GeV, as a function of event-by-event charge asymmetry, $A_{ch}$, based on data from the STAR experiment at RHIC. We find that $\pi^-$ ($\pi^+$) elliptic flow linearly increases (decreases) with charge asymmetry for most centrality bins at $\sqrt{s_{_{\rm NN}}} = \text{27 GeV}$ and higher. At $\sqrt{s_{_{\rm NN}}} = \text{200 GeV}$, the slope of the difference of $v_2$ between $\pi^-$ and $\pi^+$ as a function of $A_{ch}$ exhibits a centrality dependence, which is qualitatively similar to calculations that incorporate a chiral magnetic wave effect. Similar centrality dependence is also observed at lower energies.

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The distribution of observed charge asymmetry from STAR data.

Pion $v_2${2} as a function of observed charge asymmetry.

$v_2$ difference between $\pi^-$ and $\pi^+$ as a function of charge asymmetry with the tracking efficiency correction, for 30-40% central Au+Au collisions at 200 GeV. The errors are statistical only.

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Measurement of the transverse single-spin asymmetry in $p^\uparrow+p \to W^{\pm}/Z^0$ at RHIC

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 116 (2016) 132301, 2016.
Inspire Record 1405433 DOI 10.17182/hepdata.73263

We present the measurement of the transverse single-spin asymmetry of weak boson production in transversely polarized proton-proton collisions at $\sqrt{s} = 500~\text{GeV}$ by the STAR experiment at RHIC. The measured observable is sensitive to the Sivers function, one of the transverse momentum dependent parton distribution functions, which is predicted to have the opposite sign in proton-proton collisions from that observed in deep inelastic lepton-proton scattering. These data provide the first experimental investigation of the non-universality of the Sivers function, fundamental to our understanding of QCD.

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$P_{T}$ Recoil distribution of events simulated with PYTHIA 6.4 and reconstructed before and after the boson's PT correction has been applied.

Estimated background contributions for the $W^+ -> ev$ data yields.

Estimated background contributions for the $W^- -> ev$ data yields.

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Evidence for $e^+e^-\to\gamma\chi_{c1, 2}$ at center-of-mass energies from 4.009 to 4.360 GeV

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Chin.Phys.C 39 (2015) 041001, 2015.
Inspire Record 1329785 DOI 10.17182/hepdata.72880

Using data samples collected at center-of-mass energies of $\sqrt{s}$ = 4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process $e^+e^-\to\gamma\chi_{cJ}$ $(J = 0, 1, 2)$ and find evidence for $e^+e^-\to\gamma\chi_{c1}$ and $e^+e^-\to\gamma\chi_{c2}$ with statistical significances of 3.0$\sigma$ and 3.4$\sigma$, respectively. The Born cross sections $\sigma^{B}(e^+e^-\to\gamma\chi_{cJ})$, as well as their upper limits at the 90% confidence level are determined at each center-of-mass energy.

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The results on $e^+e^-\to\gamma\chi_{c0}$ Born cross section measurement. Shown in the table are the significance $\sigma$, detection efficiency $\epsilon$, number of signal events from the fits N$^{\rm obs}$, radiative correction factor ($1+\delta^{r}$), vacuum polarization factor ($1+\delta^{v}$), upper limit (at the 90$\%$ C.L.) on the number of signal events N$^{\rm UP}$, Born cross section $\sigma^{B}$ and upper limit (at the 90$\%$ C.L.) on the Born cross section $\sigma^{\rm UP}$ at different CME points. Numbers taken from journal version: some slight differences with respect to arXiv:1411.6336v1 in last two columns.

The results on $e^+e^-\to\gamma\chi_{c1}$ Born cross section measurement. Shown in the table are the significance $\sigma$, detection efficiency $\epsilon$, number of signal events from the fits N$^{\rm obs}$, radiative correction factor ($1+\delta^{r}$), vacuum polarization factor ($1+\delta^{v}$), upper limit (at the 90$\%$ C.L.) on the number of signal events N$^{\rm UP}$, Born cross section $\sigma^{B}$ and upper limit (at the 90$\%$ C.L.) on the Born cross section $\sigma^{\rm UP}$ at different CME points.

The results on $e^+e^-\to\gamma\chi_{c2}$ Born cross section measurement. Shown in the table are the significance $\sigma$, detection efficiency $\epsilon$, number of signal events from the fits N$^{\rm obs}$, radiative correction factor ($1+\delta^{r}$), vacuum polarization factor ($1+\delta^{v}$), upper limit (at the 90$\%$ C.L.) on the number of signal events N$^{\rm UP}$, Born cross section $\sigma^{B}$ and upper limit (at the 90$\%$ C.L.) on the Born cross section $\sigma^{\rm UP}$ at different CME points.


Observation of $Z_c(3900)^{0}$ in $e^+e^-\to\pi^0\pi^0 J/\psi$

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Rev.Lett. 115 (2015) 112003, 2015.
Inspire Record 1377204 DOI 10.17182/hepdata.73771

Using a data sample collected with the BESIII detector operating at the BEPCII storage ring, we observe a new neutral state $Z_c(3900)^{0}$ with a significance of $10.4\sigma$. The mass and width are measured to be $3894.8\pm2.3\pm3.2$ MeV/$c^2$ and $29.6\pm8.2\pm8.2$~MeV, respectively, where the first error is statistical and the second systematic. The Born cross section for $e^+e^-\to\pi^0\pi^0 J/\psi$ and the fraction of it attributable to $\pi^0 Z_c(3900)^{0}\to\pi^0\pi^0 J/\psi$ in the range $E_{cm}=4.19-4.42$ GeV are also determined. We interpret this state as the neutral partner of the four-quark candidate $Z_c(3900)^\pm$.

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Efficiencies, yields, $R=\frac{\sigma(e^+e^-\to\pi^0 Z_c(3900)^{0}\to\pi^0\pi^0 J/\psi)}{\sigma(e^+e^-\to\pi^0\pi^0 J/\psi)}$, and $\pi^0\pi^0 J/\psi$ Born cross sections at each energy point. For $N(Z_c^0)$ and $N(\pi^0\pi^0 J/\psi)$ errors and upper limits are statistical only. For $R$ and $\sigma_{\rm Born}$, the first errors and statistical and second errors are systematic. The statistical uncertainties on the efficiencies are negligible. Upper limits of $R$ (90$\%$ confidence level) include systematic errors.


Precision Measurement of the Longitudinal Double-spin Asymmetry for Inclusive Jet Production in Polarized Proton Collisions at $\sqrt{s}=200$ GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 115 (2015) 092002, 2015.
Inspire Record 1297229 DOI 10.17182/hepdata.73432

We report a new high-precision measurement of the mid-rapidity inclusive jet longitudinal double-spin asymmetry, $A_{LL}$, in polarized $pp$ collisions at center-of-mass energy $\sqrt{s}=200$ GeV. The STAR data place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep inelastic scattering (DIS), semi-inclusive DIS, and RHIC $pp$ data. The measured asymmetries provide evidence for positive gluon polarization in the Bjorken-$x$ region $x>0.05$.

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Jet neutral energy fraction (NEF) comparing data with simulations, where both are calculated with pT subtraction. This plot shows 8.4 < $p_T$ < 9.9 GeV/c.

Jet neutral energy fraction (NEF) comparing data with simulations, where both are calculated with pT subtraction. This plot shows 26.8 < $p_T$ < 31.6 GeV/c.

Inclusive jet $A_{LL}$ vs. parton jet $p_T$ for |eta|<0.5.

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Measurement of the $e^{+}e^{-} \to \eta J/\psi$ cross section and search for $e^{+}e^{-} \to \pi^{0} J/\psi$ at center-of-mass energies between 3.810 and 4.600~GeV

The BESIII collaboration Ablikim, M. ; Achasov, M.N. ; Ai, X.C. ; et al.
Phys.Rev.D 91 (2015) 112005, 2015.
Inspire Record 1355215 DOI 10.17182/hepdata.73336

Using data samples collected with the BESIII detector operating at the BEPCII collider at center-of-mass energies from 3.810 to 4.600 GeV, we perform a study of $e^{+}e^{-} \to \eta J/\psi$ and $\pi^0 J/\psi$. Statistically significant signals of $e^{+}e^{-} \to \eta J/\psi$ are observed at $\sqrt{s}$ = 4.190, 4.210, 4.220, 4.230, 4.245, 4.260, 4.360 and 4.420 GeV, while no signals of $e^{+}e^{-} \to \pi^{0} J/\psi$ are observed. The measured energy-dependent Born cross section for $e^{+}e^{-} \to \eta J/\psi$ shows an enhancement around 4.2~GeV. The measurement is compatible with an earlier measurement by Belle, but with a significantly improved precision.

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Results on $e^{+}e^{-}\to\eta J/\psi$ in data samples in which a signal is observed with a statistical significance larger than $5\sigma$. The table shows the CM energy $\sqrt{s}$, integrated luminosity $\mathcal{L}_\mathrm{int}$, number of observed $\eta$ events $N^\mathrm{obs}_{\eta}(\mu^{+}\mu^{-})$/$N^\mathrm{obs}_{\eta}(e^{+}e^{-})$ from the fit, efficiency $\epsilon_{\mu}/\epsilon_{e}$, radiative correction factor $(1+\delta^{r})$, vacuum polarization factor $(1+\delta^{v})$, Born cross section $\sigma^{B}(\mu^{+}\mu^{-})$/$\sigma^{B}(e^{+}e^{-})$ and combined Born cross section $\sigma^{B}_\mathrm{Com}$. The first uncertainties are statistical and the second systematic.

Upper limits of $e^{+}e^{-} \to \eta J/\psi$ using the $\mu^{+}\mu^{-}$ mode. The table shows the CM energy $\sqrt{s}$, integrated luminosity $\mathcal{L}_\mathrm{int}$, number of observed $\eta$ events $N^\mathrm{sg}_{\eta}$, number of background from $\eta$ sideband $N^\mathrm{sb}_{\eta}$, and from $J/\psi$ sideband $N^\mathrm{sb}_{J/\psi}$, efficiency $\epsilon$, upper limit of signal number with the consideration of selection efficiency $N^\mathrm{up}_{\eta}/\epsilon$ (at the $90\%$ C.L.), radiative correction factor $(1+\delta^{r})$, vacuum polarization factor $(1+\delta^{v})$, Born cross section $\sigma^{B}$ and upper limit on the Born cross sections $\sigma^{B}_\mathrm{up}$ (at the $90\%$ C.L.). The first uncertainties are statistical and the second systematic.

Upper limits of $e^{+}e^{-} \to \pi^{0} J/\psi$. The table shows the number of observed events in the $\pi^{0}$ signal region $N^\mathrm{sg}$, number of events in $\pi^{0}$ sideband $N^\mathrm{sb}_{\pi^{0}}$, and in $J/\psi$ sideband $N^\mathrm{sb}_{J/\psi}$, efficiency $\epsilon$, the upper limit of signal events with the consideration of the selection efficiency $N^\mathrm{up}(\mu^{+}\mu^{-})/\epsilon$ (at the $90\%$ C.L.) and the upper limit of Born cross sections $\sigma^{B}_\mathrm{up}$ (at the $90\%$ C.L.).