Measurement of Differential Branching Fractions of Inclusive ${B \to X_u \, \ell^+\, \nu_{\ell}}$ Decays

The Belle collaboration Cao, L. ; Sutcliffe, W. ; Van Tonder, R. ; et al.
Phys.Rev.Lett. 127 (2021) 261801, 2021.
Inspire Record 1895149 DOI 10.17182/hepdata.131599

The first measurements of differential branching fractions of inclusive semileptonic ${B \to X_u \, \ell^+\, \nu_{\ell}}$ decays are performed using the full Belle data set of 711 fb$^{-1}$ of integrated luminosity at the $\Upsilon(4S)$ resonance and for $\ell = e, \mu$. Differential branching fractions are reported as a function of the lepton momentum, the four-momentum-transfer squared, light-cone momenta, the hadronic mass, and the hadronic mass squared. They are obtained by subtracting the backgrounds from semileptonic ${B \to X_c \, \ell^+\, \nu_{\ell}}$ decays and other processes, and corrected for resolution and acceptance effects. The measured distributions are compared to predictions from inclusive and hybrid ${B \to X_u \, \ell^+\, \nu_{\ell}}$ calculations.

50 data tables

The measured differential branching fractions as a function of the lepton energy in the $B$ rest frame ($E_\ell^B$).

The measured differential branching fractions as a function of the four-momentum-transfer squared of the $B$ to the $X_u$ system $q^{2}$.

The measured differential branching fractions as a function of the invariant hadronic mass of the $X_u$ system ($M_X$).

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Measurement of $\phi $ meson production in $p + p$ interactions at 40, 80 and $158 \, \hbox {GeV}/c$ with the NA61/SHINE spectrometer at the CERN SPS

The NA61/SHINE collaboration Aduszkiewicz, A. ; Andronov, E.V. ; Antićić, T. ; et al.
Eur.Phys.J.C 80 (2020) 199, 2020.
Inspire Record 1749613 DOI 10.17182/hepdata.93228

Results on $\phi$ meson production in inelastic p+p collisions at CERN SPS energies are presented. They are derived from data collected by the NA61/SHINE fixed target experiment, by means of invariant mass spectra fits in the $\phi \to K^+K^-$ decay channel. They include the first ever measured double differential spectra of $\phi$ mesons as a function of rapidity $y$ and transverse momentum $p_T$ for proton beam momenta of 80 GeV/c and 158 GeV/c, as well as single differential spectra of $y$ or $p_T$ for beam momentum of 40 GeV/c. The corresponding total $\phi$ yields per inelastic p+p event are obtained. These results are compared with existing data on $\phi$ meson production in p+p collisions. The comparison shows consistency but superior accuracy of the present measurements. The emission of $\phi$ mesons in p+p reactions is confronted with that occurring in Pb+Pb collisions, and the experimental results are compared with model predictions. It appears that none of the considered models can properly describe all the experimental observables.

17 data tables

Double differential multiplicity of $\phi$ mesons produced in minimum bias p+p collisions at beam momentum of 158 GeV/c, as a function of transverse momentum $p_T$ and rapidity $y$.

Double differential multiplicity of $\phi$ mesons produced in minimum bias p+p collisions at beam momentum of 80 GeV/c, as a function of transverse momentum $p_T$ and rapidity $y$.

Transverse momentum $p_T$ spectrum of $\phi$ mesons produced in minimum bias p+p collisions at beam momentum of 40 GeV/c, in a broad rapidity $y$ bin of (0, 1.5).

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Measurement of the cross section and longitudinal double-spin asymmetry for di-jet production in polarized $pp$ collisions at $\sqrt{s}$ = 200 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.D 95 (2017) 071103, 2017.
Inspire Record 1493842 DOI 10.17182/hepdata.77208

We report the first measurement of the longitudinal double-spin asymmetry $A_{LL}$ for mid-rapidity di-jet production in polarized $pp$ collisions at a center-of-mass energy of $\sqrt{s} = 200$ GeV. The di-jet cross section was measured and is shown to be consistent with next-to-leading order (NLO) perturbative QCD predictions. $A_{LL}$ results are presented for two distinct topologies, defined by the jet pseudorapidities, and are compared to predictions from several recent NLO global analyses. The measured asymmetries, the first such correlation measurements, support those analyses that find positive gluon polarization at the level of roughly 0.2 over the region of Bjorken-$x > 0.05$.

10 data tables

Data simulation comparison (with arbitrary normalization). Di-jet invariant mass.

Data simulation comparison (with arbitrary normalization). Difference between jet pseudorapidities.

Data simulation comparison (with arbitrary normalization). Difference between jet azimuthal angles.

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Search for a massive invisible particle $X^0$ in $B^{+}\to e^{+}X^{0}$ and $B^{+}\to \mu^{+}X^{0}$ decays

The Belle collaboration Park, C.S. ; Kwon, Y.J. ; Adachi, I. ; et al.
Phys.Rev.D 94 (2016) 012003, 2016.
Inspire Record 1459050 DOI 10.17182/hepdata.78546

We present a search for a non-Standard-Model invisible particle $X^0$ in the mass range $0.1\textrm{-}1.8 \,{\rm GeV}/{c^2}$ in $B^{+}\to e^{+} X^{0}$ and $B^{+}\to \mu^{+} X^{0}$ decays. The results are obtained from a $711~{\rm fb}^{-1}$ data sample that corresponds to $772 \times 10^{6} B\bar{B}$ pairs, collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB $e^+ e^-$ collider. One $B$ meson is fully reconstructed in a hadronic mode to determine the momentum of the lepton of the signal decay in the rest frame of the recoiling partner $B$ meson. We find no evidence of a signal and set upper limits on the order of $10^{-6}$.

2 data tables

Summary of upper limits at the 90$\%$ CL for $B^+ \to e^+ X^0$.

Summary of upper limits at the 90$\%$ CL for $B^+ \to \mu^+ X^0$.


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.

6 data tables

$P_{T}$ 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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Measurement of the $\Delta^{-}-\Delta^{++}$ isobar electromagnetic mass difference

Dakhno, L.G. ; Koptev, V.P. ; Kravtsov, A.V. ; et al.
Sov.J.Nucl.Phys. 33 (1981) 59-63, 1981.
Inspire Record 1392574 DOI 10.17182/hepdata.17861

None

4 data tables

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).

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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.

10 data tables

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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Measurements of Dielectron Production in Au$+$Au Collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV from the STAR Experiment

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.C 92 (2015) 024912, 2015.
Inspire Record 1357992 DOI 10.17182/hepdata.73504

We report on measurements of dielectron ($e^+e^-$) production in Au$+$Au collisions at a center-of-mass energy of 200 GeV per nucleon-nucleon pair using the STAR detector at RHIC. Systematic measurements of the dielectron yield as a function of transverse momentum ($p_{\rm T}$) and collision centrality show an enhancement compared to a cocktail simulation of hadronic sources in the low invariant-mass region ($M_{ee}<$ 1 GeV/$c^2$). This enhancement cannot be reproduced by the $\rho$-meson vacuum spectral function. In minimum-bias collisions, in the invariant-mass range of 0.30 $-$ 0.76 GeV/$c^2$, integrated over the full $p_{\rm T}$ acceptance, the enhancement factor is 1.76 $\pm$ 0.06 (stat.) $\pm$ 0.26 (sys.) $\pm$ 0.29 (cocktail). The enhancement factor exhibits weak centrality and $p_{\rm T}$ dependence in STAR's accessible kinematic regions, while the excess yield in this invariant-mass region as a function of the number of participating nucleons follows a power-law shape with a power of 1.44 $\pm$ 0.10. Models that assume an in-medium broadening of the $\rho$ meson spectral function consistently describe the observed excess in these measurements. Additionally, we report on measurements of $\omega$ and $\phi$-meson production through their $e^+e^-$ decay channel. These measurements show good agreement with Tsallis Blast-Wave model predictions as well as, in the case of the $\phi$-meson, results through its $K^+K^-$ decay channel. In the intermediate invariant-mass region (1.1$<M_{ee}<$ 3 GeV/$c^2$), we investigate the spectral shapes from different collision centralities. Physics implications for possible in-medium modification of charmed hadron production and other physics sources are discussed.

50 data tables

Estimated electron purity vs. momentum in 200 GeV Au + Au collisions.

Acceptance correction factor for unlike-sign and like-sign pair difference from 200 GeV Au+Au minimum-bias collisions.

Ratio of the same-event like-sign to the mixed event unlike-sign distributions.

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Charged-to-neutral correlation at forward rapidity in Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.C 91 (2015) 034905, 2015.
Inspire Record 1311834 DOI 10.17182/hepdata.73610

Event-by-event fluctuations of the ratio of inclusive charged to photon multiplicities at forward rapidity in Au+Au collision at $\sqrt{s_{NN}}$=200 GeV have been studied. Dominant contribution to such fluctuations is expected to come from correlated production of charged and neutral pions. We search for evidences of dynamical fluctuations of different physical origins. Observables constructed out of moments of multiplicities are used as measures of fluctuations. Mixed events and model calculations are used as baselines. Results are compared to the dynamical net-charge fluctuations measured in the same acceptance. A non-zero statistically significant signal of dynamical fluctuations is observed in excess to the model prediction when charged particles and photons are measured in the same acceptance. We find that, unlike dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated by correlation due to particle decay. Results are compared to the expectations based on the generic production mechanism of pions due to isospin symmetry, for which no significant (<1%) deviation is observed.

21 data tables

Multiplicity distributions of raw charged particles and photons.

The $v_{dyn}$ and the three terms of $v_{dyn}$ vs $\sqrt{\langle N_{ch}\rangle \langle N_{\gamma}\rangle }$ for real events. $\omega_{ch}^{real}$ is plotted.

The $v_{dyn}$ and the three terms of $v_{dyn}$ vs $\sqrt{\langle N_{ch}\rangle \langle N_{\gamma}\rangle }$ for mixed events. $\omega_{ch}^{mixed}$ is plotted.

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The $\Lambda\Lambda$ Correlation Function in Au+Au collisions at $\sqrt{s_{NN}}=$ 200 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.Lett. 114 (2015) 022301, 2015.
Inspire Record 1311513 DOI 10.17182/hepdata.73492

We present $\Lambda\Lambda$ correlation measurements in heavy-ion collisions for Au+Au collisions at $\sqrt{s_{NN}}= 200$ GeV using the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). The Lednick\'{y}-Lyuboshitz analytical model has been used to fit the data to obtain a source size, a scattering length and an effective range. Implications of the measurement of the $\Lambda\Lambda$ correlation function and interaction parameters for di-hyperon searches are discussed.

4 data tables

The invariant mass distribution for $\Lambda$ and $\bar{\Lambda}$ produced in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV, for 0-80% centrality. The $\Lambda$ and $\bar{\Lambda}$ candidates lying in the mass range 1.112 to 1.120 GeV/c^2 were selected for the correlation measurement.

The $\Lambda\Lambda$ and $\bar{\Lambda}\bar{\Lambda}$ correlation function in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV, for 0-80% centrality.

The combined $\Lambda\Lambda$ and $\bar{\Lambda}\bar{\Lambda}$ correlation function for 0-80% centrality Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

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