We report on the production characteristics and total cross section for 9 beauty hadron pairs produced by a 600 GeV/ c π − beam, the first such information in this energy region. The events were detected in the hybrid emulsion spectrometer of Fermilab Experiment E653. The measured pair cross section for all χ F , assuming linear A dependence, is 33±11 (stat.)±6(syst.) nb/nucleon. Fits of the inclusive single-hadron production distribution to the forms d σ d χ F ∝ (1−|χ F −χ 0 |) n and d σ d p T 2 ∝ exp (−bp t 2 ) give n=5.0 −2.1−1.7 +2.7+1.7 , χ 0 =0.06 −0.07−0.03 +0.06+0.02 , and b=0.13 −0.04−0.02 +0.05+0.02 ( GeV /c −2 . .The pairs tend to be produced back-to-back.

We present total and differential cross sections for charm mesons produced in 600 GeV/ c π - emulsion interactions. Fits to d 2 σ / dx F dp T 2 ∞ (1−| x F |) n exp (- bp T 2 ) for 676 electronically reconstructed D mesons with x F >0 give n =4.25±0.24 ( stat .)±0.23 ( syst .) and b =0.76±0.03±0.03 ( GeV / c ) -2 . The total inclusive D + and D 0 cross sections are σ ( π - N → D ± ; x F >0) = 8.66±0.46±1.96 μb nucleon and σ(π - N→D 0 D 0 ; x F >0)=22.05±1.37±4.82μb nucleonk, where a linear dependence on the mean atomic weight of the target is assumed. These results are compared to next-to-leading order QCD predictions.

We report results on D 0 and D + production in proton-emulsion interactions at s =38.7 GeV. A fit to the form (1−| x F |) n exp (−bp 2 T ) yields n=6.9 +1.9 −1.8 and b=0.84 +0.10 −0.08 (GeV/ c ) −2 . The total inclusive cross section, is assuming linear A dependence, is measured to be 38±3(stat.) ±13 (sys.) μ b for the D 0 and 38±9±14 μ b for the D + . A comparison of these results with previous measurements indicates that nuclear effects do not strongly influence charm production. The predictions of QCD are in good agreement with our data.

We present results on charm pair correlations measured in proton-emulsion interactions at s =38.7 GeV. The predictions of leading order QCD for the distributions in invariant mass, rapidity gap, x F , and polar angle in the charm pair CMS are qualitatively consistent with our measurements. The mean p T of the pairs is equal within errors to that measured in dilepton production at the same energy and mass range.

A search for charm production in the coherent diffractive dissociation reaction pSi→XSi was carried out for the modes D 0 → K − π + , D 0 → K − π + π + π − , and D + → K − π + π + . No charm signals were observed, and the 90% confidence level upper limit for coherent charm pair production was determined to be 26 μ b per silicon nucleus. The results are interpreted as an upper limit of 0.2% on the amount of intrinsic charm in the proton.

We have found 122 charmed-particle decays among 3855 neutrino interactions located in the fiducial volume of a hybrid emulsion spectrometer installed in the Fermilab wide-band neutrino beam. We obtain an average relative charmed-particle production cross section of σ(ν μ → c μ − ) σ(ν μ →μ − ) =4.9 −0.6 +0.7 % , at an average neutrino energy of 22 GeV. We also obtain a production rate of σ(ν μ → c c ν μ ) σ(ν μ →ν μ ) =0.13 −0.11 +0.31 % , if we assume that there was an undetected muon, a limit of σ(ν μ → c c μ − ) σ(ν μ → c μ − )<3% (90% CL ) can be obtained. Other cross section ratios and limits are also presented.

We report a measurement of the electroweak parameters sin2θw and ϱ based on the ratios of neutral current to charged current events measured in the Fermilab narrow-band neutrino beam at energies of 30–240 GeV. The data are fully corrected for radiative effects, heavy-quark production, and other effects. The best value for sin2θw obtained, sin2θw=0.239±0.011, is consistent with the most recent values fromW andZ production, as well as from other neutrino experiments.

A measurement of continuum dimuon production in proton-copper collisions at 800-GeV incident energy is presented. The dimuons observed in this experiment cover the mass range from 6.5 to 18 GeV near y=0 in the proton-nucleon center-of-momentum frame. Scaling forms of the cross section for the continuum are compared with the results of other experiments in the context of the parton model and quantum chromodynamics. The present limitations of such scaling comparisons are discussed.

We have measured the polarization of Λ and Λ hyperons produced by 800 GeV protons on a Be target at a fixed targeting angle of 4.8 mrad. Comparison with previous data at 400 GeV production energy and twice the targeting angle shows no significant energy dependence for the Λ polarization. This is in striking contrast to the energy dependence found for σ + and Ξ − polarizations. We find no evidence for Λ polarization at 800 GeV.

Experiment E735 searched for evidence of the transition to quark-gluon plasma in p p collisions at √ s = 1.8 TeV. Using data from a high statistics run in 1988–1989, results are presented on multiplicity distributions, hyperon and phi production, and Bose-Einstein correlations. Some data were also taken at lower collision energies and results will be compared to previous experiments.

Inelastic scattering of 490 GeV μ + from deuterium and xenon nuclei has been studied for x Bj > s .001. The ratio of the xenon/deuterium cross section per nucleon is observed to vary with x Bj , with a depletion in the kinematic range 0.001 < x Bj < 0.025 which exhibits no significant Q 2 dependence. An electromagnetic calorimeter was used to verify the radiative corrections.

The fermilab high-energy photoproduction experiment E687 provides a sample of approximately 90 events of the decay mode D + s → φμ + ν . The ratios of the form factors governing the decay are measured to be R v =1.8±0.9±0.2 and R 2 = 1.1±0.8±0.1, implying a polarization of Г 1 /Г t = 1.0±0.5±0.1 for the electron decay, consistent with our measurement of the form factor for the decay D + → K ∗0 μ + ν .

We report evidence for the Cabibbo-suppressed decay of the charm baryon Λ c + into the final state pK − K + . The analysis is performed on data collected by high energy photoproduction experiment E687 during the 1990–1991 Fermilab fixed target run. The branching ratio of the decay Λ c + → pK − K + relative to the non-suppressed Λ c + → pK − π + is measured to be BR( pK − K + / pK − π + ) = 0.096 ± 0.029 ± 0.010. The upper limit of the decay into pø relative to the inclusive pK − K + decay is measured to be BR( pø / pK − K + < 58% at the 90% confidence level.

Measurements of elastic photoproduction cross sections for the J / ψ meson from 100 GeV to 375 GeV are presented. The results indicate that the cross section increases slowly in this range. The shape of the energy dependence agrees well with the photon-gluon fusion model prediction.

Charged hadronic four-body decays of D 0 mesons have been studied in the E687 photoproduction experiment at Fermilab. Branching ratios relative to the D 0 → K − π + π + π − decay mode for the Cabibbo-suppressed decays D 0 → π − π + π − π + , D 0 → K − K + π − π + have been measured and the first evidence of the D 0 → K − K + K − π + decay mode is reported. An analysis of the D 0 → K − K + π − π + resonance structure is also presented.

Results for the Cabibbo suppressed semileptonic decays D 0 → π − e + ν and D 0 → π − μ + ν (charge conjugates are implied) are reported by Fermilab photoproduction experiment E687. We find 45.4 ± 13.3 events in the electron mode and 45.6 ± 11.8 in the muon mode. The relative branching ratio BR (D 0 →π − l + v) BR (D 0 →K − l + v) for the combined sample is measured to be 0.101 ± 0.020 (stat.) ± 0.003 (syst.) 14 .

We report measurements of charm particle production asymmetries from the Fermilab photoproduction experiment E687. An asymmetry in the rate of production of charm versus anticharm particles is expected to arise primarily from fragmentation effects. We observe statistically significant asymmetries in the photoproduction of D + , D ∗+ and D 0 mesons and find small (but statistically weak) asymmetries in the production of the D s + meson and the Λ c + baryon. Our inclusive photoproduction asymmetries are compared to predictions from nonperturbative models of charm quark fragmentation.

We report on the study of charm baryons decaying to Λ c + : Λ c ★+ (2625) → Λ c + π + π − , Λ c ★+ (2593) → Λ c + π + π − , Σ c 0 → Λ c + π − and Σ c ++ → Λ c + π + . We present a confirmation of the state Λ c ∗+ (2593) and determine its mass difference to be M ( Λ c ★+ (2593)) − M ( Λ c + ) = 309.2 ± 0.7 ± 0.3 MeV/ c 2 . We determine the lower limit on the resonant branching ratio to be BR (Λ c ★+ (2593) → Σ c π ± Λ c ★+ (2593) → Λ c + π + π − ) > 0.51 (90% c.l.). We also measure the mass differences M ( Σ c 0 ) − M ( Λ c + ) = 166.6±0.5±0.6 MeV/ c 2 and M ( Σ c ++ ) − M ( Λ c + ) = 167.6±0.6±0.6 MeV/ c 2 . Finally, we measure the relative photoproduction cross sections for Λ c ★+ and Σ c with respect to the (inclusive) photoproduction cross section for Λ c + .

The analyzing power A N of proton-proton, proton-hydrocarbon, and antiproton-hydrocarbon, scattering in the Coulomb-nuclear interference region has been measured using thhe 185 GeV/ c Fermilab polarized-proton and -antiproton beams. The results are found to be consistent with theoretical predictions within statistical uncertainties.

Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH) is studied using the \minerva detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for $\bar{\nu}_e$ appearance oscillation experiments. The differential cross sections for $\pi^0$ momentum and production angle, for events with a single observed $\pi^0$ and no charged pions, are presented and compared to model predictions. These results comprise the first measurement of the $\pi^0$ kinematics for this process.

An experiment has been performed with the Fermilab 30-inch bubble chamber and Downstream Particle Identifier to study inclusive charged pion production in the high energy interactions of π±,K+,p and\(\bar p\) with thin foils of magnesium, silver and gold. The laboratory rapidity and transverse momentum distributions are presented separately for π+ and π− production. Comparisons are made with data from hadron-proton interactions and theA dependence of the cross sections in the different kinematic regions is discussed. We investigate the dependence of the cross sections on the number of observed protons ejected from the nucleus. By using our π−A data from two different beam energies, we study the energy dependence of these spectra. Comparisons are made with the VENUS string model Monte Carlo.

We report on the analysis of Charmonium and Bottomium states produced in p-Si interactions at s =38.7 GeV . The data have been collected with the open geometry spectrometer of the E771 Experiment at the FNAL High Intensity Lab. J ψ , ψ′ and γ total cross sections as well as the ratio B(ψ′ → μμ)σ(ψ′) (B( J ψ → μμ)σ( J ψ )) have been measured. Results are compared with theoretical predictions and with results at other energies.

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%.

We detected 1–10 MeV neutrons at laboratory angles from 80° to 140° in coincidence with 470 GeV muons deep inelastically scattered from H, D, C, Ca, and Pb targets. The neutron energy spectrum for Pb can be fitted with two components with temperature parameters of 0.7 and 5.0 MeV. The average neutron multiplicity for 40<ν<400 GeV is about 5 for Pb, and less than 2 for Ca and C. These data are consistent with a process in which the emitted hadrons do not interact with the rest of the nucleus within distances smaller than the radius of Ca, but do interact within distances on the order of the radius of Pb in the measured kinematic range. For all targets the lack of high nuclear excitation is surprising.

The first evidence for X(3872) production in relativistic heavy ion collisions is reported. The X(3872) production is studied in lead-lead (PbPb) collisions at a center-of-mass energy of $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV per nucleon pair, using the decay chain X(3872) $\to$ J$/\psi\, \pi^+\pi^- \to$ $\mu^+\mu^-\pi^+\pi^-$. The data were recorded with the CMS detector in 2018 and correspond to an integrated luminosity of 1.7 nb$^{-1}$. The measurement is performed in the rapidity and transverse momentum ranges $|y|$ $\lt$ 1.6 and 15 $\lt$ $p_\mathrm{T}$ $\lt$ 50 GeV$/c$. The significance of the inclusive X(3872) signal is 4.2 standard deviations. The prompt X(3872) to $\psi$(2S) yield ratio is found to be $\rho^\mathrm{PbPb} = $ 1.08 $\pm$ 0.49 (stat) $\pm$ 0.52 (syst), to be compared with typical values of 0.1 for pp collisions. This result provides a unique experimental input to theoretical models of the X(3872) production mechanism, and of the nature of this exotic state.

Measurements of inclusive spectra and mean multiplicities of $\pi^\pm$, K$^\pm$, p and $\bar{\textrm{p}}$ produced in inelastic p+p interactions at incident projectile momenta of 20, 31, 40, 80 and 158 GeV/c ($\sqrt{s} = $ 6.3, 7.7, 8.8, 12.3 and 17.3 GeV, respectively) were performed at the CERN Super Proton Synchrotron using the large acceptance NA61/SHINE hadron spectrometer. Spectra are presented as function of rapidity and transverse momentum and are compared to predictions of current models. The measurements serve as the baseline in the NA61/SHINE study of the properties of the onset of deconfinement and search for the critical point of strongly interacting matter.

The hydrodynamic flow-like behavior of charged hadrons in high-energy lead-lead collisions is studied through multiparticle correlations. The elliptic anisotropy values based on different orders of multiparticle cumulants, $v_{2}\{2k\}$, are measured up to the tenth order ($k$ = 5) as functions of the collision centrality at a nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV. The data were recorded by the CMS experiment at the LHC and correspond to an integrated luminosity of 0.607 nb$^{-1}$. A hierarchy is observed between the coefficients, with $v_{2}\{2\} > v_{2}\{4\} \gtrsim v_{2}\{6\} \gtrsim v_{2}\{8\} \gtrsim v_{2}\{10\}$. Based on these results, centrality-dependent moments for the fluctuation-driven event-by-event $v_{2}$ distribution are determined, including the skewness, kurtosis and, for the first time, superskewness. Assuming a hydrodynamic expansion of the produced medium, these moments directly probe the initial-state geometry in high-energy nucleus-nucleus collisions.

Results on two-particle $\Delta\eta\Delta\phi$ correlations in inelastic p+p interactions at 20, 31, 40, 80, and 158~GeV/c are presented. The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The data show structures which can be attributed mainly to effects of resonance decays, momentum conservation, and quantum statistics. The results are compared with the EPOS and UrQMD models.

None

This paper presents measurements of production cross sections and inelastic cross sections for the following reactions: 60 GeV/$c$ protons with C, Be, Al targets and 120 GeV/$c$ protons with C and Be targets. The analysis was performed using the NA61/SHINE spectrometer at the CERN SPS. First measurements were obtained using protons at 120 GeV/$c$, while the results for protons at 60 GeV/$c$ were compared with previously published measurements. These interaction cross section measurements are critical inputs for neutrino flux prediction in current and future accelerator-based long-baseline neutrino experiments.

Precise knowledge of hadron production rates in the generation of neutrino beams is necessary for accelerator-based neutrino experiments to achieve their physics goals. NA61/SHINE, a large-acceptance hadron spectrometer, has recorded hadron+nucleus interactions relevant to ongoing and future long-baseline neutrino experiments at Fermi National Accelerator Laboratory. This paper presents three analyses of interactions of 60 GeV/$c$ $\pi^+$ with thin, fixed carbon and beryllium targets. Integrated production and inelastic cross sections were measured for both of these reactions. In an analysis of strange, neutral hadron production, differential production multiplicities of $K^0_{S}$, $\Lambda$ and anti-$\Lambda$ were measured. Lastly, in an analysis of charged hadron production, differential production multiplicities of $\pi^+$, $\pi^-$, $K^+$, $K^-$ and protons were measured. These measurements will enable long-baseline neutrino experiments to better constrain predictions of their neutrino flux in order to achieve better precision on their neutrino cross section and oscillation measurements.

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.

The production of $\Xi(1321)^{-}$ and $\overline{\Xi}(1321)^{+}$ hyperons in inelastic p+p interactions is studied in a fixed target experiment at a beam momentum of 158 GeV/textitc. Double differential distributions in rapidity y and transverse momentum $p_{T}$ are obtained from a sample of 33M inelastic events. They allow to extrapolate the spectra to full phase space and to determine the mean multiplicity of both $\Xi^{-}$ and $\overline{\Xi}^{+}$. The rapidity and transverse momentum spectra are compared to transport model predictions. The $\Xi^{-}$ mean multiplicity in inelastic p+p interactions at 158~\GeVc is used to quantify the strangeness enhancement in A+A collisions at the same centre-of-mass energy per nucleon pair.

Measurements of the $\pi^{\pm}$, $K^{\pm}$, and proton double differential yields emitted from the surface of the 90-cm-long carbon target (T2K replica) were performed for the incoming 31 GeV/c protons with the NA61/SHINE spectrometer at the CERN SPS using data collected during 2010 run. The double differential $\pi^{\pm}$ yields were measured with increased precision compared to the previously published NA61/SHINE results, while the $K^{\pm}$ and proton yields were obtained for the first time. A strategy for dealing with the dependence of the results on the incoming proton beam profile is proposed. The purpose of these measurements is to reduce significantly the (anti)neutrino flux uncertainty in the T2K long-baseline neutrino experiment by constraining the production of (anti)neutrino ancestors coming from the T2K target.

The measurement of $K^{*}(892)^0$ resonance production via its $K^{+}\pi^{-}$ decay mode in inelastic p+p collisions at beam momentum 158 GeV/$c$ ($\sqrt{s_{NN}}=17.3$ GeV) is presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The $\textit{template}$ method was used to extract the $K^{*}(892)^0$ signal and double differential transverse momentum and rapidity spectra were obtained. The full phase-space mean multiplicity of $K^{*}(892)^0$ mesons was found to be $(78.44 \pm 0.38 \mathrm{(stat)} \pm 6.0 \mathrm{(sys)) \cdot 10^{-3}}$. The NA61/SHINE results are compared with the E$_{POS}$1.99 and Hadron Resonance Gas models as well as with world data from p+p and nucleus-nucleus collisions.

The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconfinement in hadron matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of $\pi^\pm$, $K^\pm$, $p$ and $\bar{p}$ produced in the 20$\%$ most $central$$^7$Be+$^9$Be collisions at beam momenta of 19$A$, 30$A$, 40$A$, 75$A$ and 150$A$ GeV/$c$. The energy dependence of the $K^\pm$/$\pi^\pm$ ratios as well as of inverse slope parameters of the $K^\pm$ transverse mass distributions are close to those found in inelastic $p$+$p$ reactions. The new results are compared to the world data on $p$+$p$ and Pb+Pb collisions as well as to predictions of the EPOS, UrQMD, AMPT, PHSD and SMASH models.

The NA61/SHINE collaboration studies at the CERN Super Proton Synchrotron (SPS) the onset of deconfinement in hadronic matter by the measurement of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra and mean multiplicities of $\pi^{-}$ mesons produced in the 5\% most \textit{central} $^7$Be+$^9$Be collisions at beam momenta of 19$A$, 30$A$, 40$A$, 75$A$ and 150$A$ GeV/$c$ obtained by the so-called $h^-$ method which does not require any particle identification. The shape of the transverse mass spectra differs from the shapes measured in central Pb+Pb collisions and inelastic p+p interactions. The normalized width of the rapidity distribution decreases with increasing collision energy and is in between the results for inelastic nucleon-nucleon and central Pb+Pb collisions. The mean multiplicity of pions per wounded nucleon in \textit{central} $^7$Be+$^9$Be collisions is close to that in central Pb+Pb collisions up to 75$A$GeV/$c$. However, at the top SPS energy the result is close to the one for inelastic nucleon-nucleon interactions. The results are discussed in the context of predictions for the onset of deconfinement at the CERN SPS collision energies.

We measure triangular flow relative to the reaction plane at 3 GeV center-of-mass energy in Au+Au collisions at the BNL Relativistic Heavy Ion Collider. A significant $v_3$ signal for protons is observed, which increases for higher rapidity, higher transverse momentum, and more peripheral collisions. The triangular flow is essentially rapidity-odd with a slope at mid-rapidity, $dv_3/dy|_{(y=0)}$, opposite in sign compared to the slope for directed flow. No significant $v_3$ signal is observed for charged pions and kaons. Comparisons with models suggest that a mean field potential is required to describe these results, and that the triangular shape of the participant nucleons is the result of stopping and nuclear geometry.

The nuclear modification factors of J/$\psi$ and $\psi$(2S) mesons are measured in PbPb collisions at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}} =$ 5.02 TeV. The analysis is based on PbPb and pp data samples collected by CMS at the LHC in 2015, corresponding to integrated luminosities of 464 $\mu$b$^{-1}$ and 28 pb$^{-1}$, respectively. The measurements are performed in the dimuon rapidity range of $|y| <$ 2.4 as a function of centrality, rapidity, and transverse momentum (p$_\mathrm{T}$) from p$_\mathrm{T}=$ 3 GeV/$c$ in the most forward region and up to 50 GeV/$c$. Both prompt and nonprompt (coming from b hadron decays) mesons are observed to be increasingly suppressed with centrality, with a magnitude similar to the one observed at $\sqrt{s_{\mathrm{NN}}}=$ 2.76 TeV for the two J/$\psi$ meson components. No dependence on rapidity is observed for either prompt or nonprompt J/$\psi$ mesons. An indication of a lower prompt J/$\psi$ meson suppression at p$_\mathrm{T} >$ 25 GeV/$c$ is seen with respect to that observed at intermediate p$_\mathrm{T}$. The prompt $\psi$(2S) meson yield is found to be more suppressed than that of the prompt J/$\psi$ mesons in the entire p$_\mathrm{T}$ range.