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CROSS SECTION ON NEUTRON CALCULATED FROM DEUTERIUM MEASUREMENTS USING THE NUCLEON SPECTATOR MODEL.
The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured open heavy-flavor production in minimum bias Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV via the yields of electrons from semileptonic decays of charm and bottom hadrons. Previous heavy-flavor electron measurements indicated substantial modification in the momentum distribution of the parent heavy quarks due to the quark-gluon plasma created in these collisions. For the first time, using the PHENIX silicon vertex detector to measure precision displaced tracking, the relative contributions from charm and bottom hadrons to these electrons as a function of transverse momentum are measured in Au$+$Au collisions. We compare the fraction of electrons from bottom hadrons to previously published results extracted from electron-hadron correlations in $p$$+$$p$ collisions at $\sqrt{s_{_{NN}}}=200$ GeV and find the fractions to be similar within the large uncertainties on both measurements for $p_T>4$ GeV/$c$. We use the bottom electron fractions in Au$+$Au and $p$$+$$p$ along with the previously measured heavy flavor electron $R_{AA}$ to calculate the $R_{AA}$ for electrons from charm and bottom hadron decays separately. We find that electrons from bottom hadron decays are less suppressed than those from charm for the region $3
Bottom and charm hadron invariant yields as a function of $p_{T}$.
Bottom hadron fraction with respect to heavy flavor electron as a function of $p_{T}$.
Bottom and charm hadron $R_{AA}$ as a function of $p_{T}$.
We present measurements of $e^+e^-$ production at midrapidity in Au$+$Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass ($m_{ee} <$ 5 GeV/$c^2$) and pair transverse momentum ($p_T$ $<$ 5 GeV/$c$), for minimum bias and for five centrality classes. The \ee yield is compared to the expectations from known sources. In the low-mass region ($m_{ee}=0.30$--0.76 GeV/$c^2$) there is an enhancement that increases with centrality and is distributed over the entire pair \pt range measured. It is significantly smaller than previously reported by the PHENIX experiment and amounts to $2.3\pm0.4({\rm stat})\pm0.4({\rm syst})\pm0.2^{\rm model}$ or to $1.7\pm0.3({\rm stat})\pm0.3({\rm syst})\pm0.2^{\rm model}$ for minimum bias collisions when the open-heavy-flavor contribution is calculated with {\sc pythia} or {\sc mc@nlo}, respectively. The inclusive mass and $p_T$ distributions as well as the centrality dependence are well reproduced by model calculations where the enhancement mainly originates from the melting of the $\rho$ meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region ($m_{ee}$ = 1.2--2.8 GeV/$c^2$), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons.
Cocktail of hadronic sources for the 2010 run using the PYTHIA generator for the open heavy flavor contributions.
Invariant mass spectrum of $e^+e^-$ pairs in MB Au+Au collisions within the PHENIX acceptance compared to the cocktail of expected decays.
$Au collisions at $\sqrt{s_{NN}}$=200 GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the $R=0.3$ anti-$k_{t}$ algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multi-wire proportional chambers, and the jet transverse momentum ($p_T$) spectra are corrected for the detector response. Spectra are reported for jets with $12
Measured anti-$k_T$, $R$ = 0.3 jet yields in $d$+Au collisions, and the measured and calculated jet cross section in $p$+$p$ collisions.
$R_{dAu}$ as a function of $p_T$.
$R_{CP}$ as a function of $p_T$.
A new set of measurements of the top quark mass are presented, based on the proton-proton data recorded by the CMS experiment at the LHC at sqrt(s) = 8 TeV corresponding to a luminosity of 19.7 inverse femtobarns. The top quark mass is measured using the lepton + jets, all-jets and dilepton decay channels, giving values of 172.35 +/- 0.16 (stat) +/- 0.48 (syst) GeV, 172.32 +/- 0.25 (stat) +/- 0.59 (syst) GeV, and 172.82 +/- 0.19 (stat) +/- 1.22 (syst) GeV, respectively. When combined with the published CMS results at sqrt(s) = 7 TeV, they provide a top quark mass measurement of 172.44 +/- 0.13 (stat) +/- 0.47 (syst) GeV. The top quark mass is also studied as a function of the event kinematical properties in the lepton + jets decay channel. No indications of a kinematic bias are observed and the collision data are consistent with a range of predictions from current theoretical models of t t-bar production.
Measurement of $m_{t}$ as a function of the transverse momentum of the hadronically decaying top quark.
Measurement of $m_{t}$ as a function of the invariant mass of the tt¯ system.
Measurement of $m_{t}$ as a function of the transverse momentum of the tt¯ system.
The dimuon production in 200 GeV/nucleon O-U, O-Cu, S-U and p-U reactions is studied in function of transverse energy E T produced by the collision. The J / ψ production relative to continuum events is suppressed for heavy ion induced reactions when E T increases. This suppression is enhanced at low transverse momentum. The π and K meson distributions extracted from the data, have, for each reaction, a similar average transverse momentum which increases only slightly with the transverse energy.
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K − p elastic scattering at 10 GeV/ c is studied on ∼3600 bubble chamber events. The elastic cross section is found to be σ el = (3.20 ± 0.14)mb and the ratio σ el σ tot = (0.142 ± 0.006) , that is below the upper limit of 0.185 suggested in a model by Van Hove. The value of the forward differential cross section is consistent with zero real part to the scattering amplitude. The slope of d σ d t is similar to that for π ± and greater than that of K + , with no evidence for shrinkage of the diffraction peak. No events of backward scattering were observed. The Regge-pole model of Phillips and Rarita gives a good fit to the data.
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The spin correlation parameter C NN has been measured for n-p elastic scattering at 181 MeV. A comparison with predictions from various phase shift sets and potential models reveals sizeable deviations from the for the data Paris potential and Saclay phase shifts. For the Paris potential the deviations are directly related to an overprediction of the 3 D 2 phase shift parameter.
Numerical values of data supplied by J. Sowinski.
Differential cross section and polarization distributions are presented for elastic p p scattering at incident momenta of 1.73, 2.13, 2.37 and 2.97 GeV/ c . The data have been analysed in terms of a 5-parameter diffraction model. In terms of this model the difference in the shape of the differential cross sections for p p and pp elastic scattering is a result of the strong absorption in the p p system.
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A measurement is presented of differential cross sections for the Higgs boson (H) production in pp collisions at sqrt(s) = 8 TeV. The analysis exploits the H to gamma gamma decay in data corresponding to an integrated luminosity of 19.7 inverse femtobarns collected by the CMS experiment at the LHC. The cross section is measured as a function of the kinematic properties of the diphoton system and of the associated jets. Results corrected for detector effects are compared with predictions at next-to-leading order and next-to-next-to-leading order in perturbative quantum chromodynamics, as well as with predictions beyond the standard model. For isolated photons with pseudorapidities abs(eta) < 2.5, and with the photon of largest and next-to-largest transverse momentum (pt[gamma]) divided by the diphoton mass m[gamma-gamma] satisfying the respective conditions of pt[gamma] / m[gamma-gamma] > 1/3 and > 1/4, the total fiducial cross section is 32 +/- 10 fb.
Values of the pp $\to$ H $\to \gamma\gamma$ differential cross sections as a function of kinematic observables as measured in data and as predicted in SM simulations. For each observable the fit to $m_{\gamma\gamma}$ is performed simultaneously in all the bins. Since the signal mass is profiled for each observable, the best fit $\hat{m}_{\rm{H}}$ varies from observable to observable.
Values of the pp $\to$ H $\to \gamma\gamma$ differential cross sections as a function of $p_{\rm{T}}^{\gamma\gamma}$ as measured in data. For each observable the fit to $m_{\gamma\gamma}$ is performed simultaneously in all the bins. Since the signal mass is profiled for each observable, the best fit $\hat{m}_{\rm{H}}$ varies from observable to observable.
Values of the pp $\to$ H $\to \gamma\gamma$ differential cross sections as a function of |$\cos\theta^{\ast}$| as measured in data. For each observable the fit to $m_{\gamma\gamma}$ is performed simultaneously in all the bins. Since the signal mass is profiled for each observable, the best fit $\hat{m}_{\rm{H}}$ varies from observable to observable.
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