L. Malferrari

Bio: L. Malferrari is an academic researcher from University of Bologna. The author has contributed to research in topics: Collider Detector at Fermilab & Tevatron. The author has an hindex of 25, co-authored 85 publications receiving 2625 citations. Previous affiliations of L. Malferrari include University of Southampton.

Measurement of the J/ψ meson and b-hadron production cross sections in pp̄ collisions at √s = 1960 GeV

Abstract: The authors present a new measurement of the inclusive and differential production cross sections of J/{psi} mesons and b-hadrons in proton-antiproton collisions at {radical}s = 1960 GeV The data correspond to an integrated luminosity of 397 pb{sup -1} collected by the CDF Run II detector They find the integrated cross section for inclusive J/{psi} production for all transverse momenta from 0 to 20 GeV/c in the rapidity range |y| 125 GeV/c They find the total cross section for b-hadrons, including both hadrons and anti-hadrons, decaying to J/{psi} with transverse momenta greater than 125 GeV/c in the rapidity range |y(J/{psi})| < 06, is 0330 {+-} 0005(stat){sub -0033}{sup +0036}(syst) {mu}b Using a Monte Carlo simulation of the decay kinematics of b-hadrons to all final states containing a J/{psi}, they extract the first measurement of the total single b-hadron cross section down to zero transverse momentum at {radical}s = 1960 GeV They find the total single b-hadron cross section integrated over all transverse momenta for b-hadrons in themore » rapidity range |y| < 06 to be 176 {+-} 04(stat){sub -23}{sup +25}(syst) {mu}b« less

Measurement of the J/psi meson and b-hadron production cross sections in p(p)over-bar collisions at root s=1960 GeV RID C-1693-2008 RID G-1087-2011 RID E-4473-2011

Abstract: We present a new measurement of the inclusive and differential production cross sections of $J/\ensuremath{\psi}$ mesons and $b$ hadrons in proton-antiproton collisions at $\sqrt{s}=1960\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}$. The data correspond to an integrated luminosity of $39.7\text{ }\text{ }{\mathrm{p}\mathrm{b}}^{\ensuremath{-}1}$ collected by the CDF run II detector. We find the integrated cross section for inclusive $J/\ensuremath{\psi}$ production for all transverse momenta from 0 to $20\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/c$ in the rapidity range $|y|l0.6$ to be $4.08\ifmmode\pm\else\textpm\fi{}0.02(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}{)}_{\ensuremath{-}0.33}^{+0.36}(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\text{ }\text{ }\ensuremath{\mu}\mathrm{b}$. We separate the fraction of $J/\ensuremath{\psi}$ events from the decay of the long-lived $b$ hadrons using the lifetime distribution in all events with ${p}_{T}(J/\ensuremath{\psi})g1.25\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/c$. We find the total cross section for $b$ hadrons, including both hadrons and antihadrons, decaying to $J/\ensuremath{\psi}$ with transverse momenta greater than $1.25\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/c$ in the rapidity range $|y(J/\ensuremath{\psi})|l0.6$ is $0.330\ifmmode\pm\else\textpm\fi{}0.005(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}{)}_{\ensuremath{-}0.033}^{+0.036}(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\text{ }\text{ }\ensuremath{\mu}\mathrm{b}$. Using a Monte Carlo simulation of the decay kinematics of $b$ hadrons to all final states containing a $J/\ensuremath{\psi}$, we extract the first measurement of the total single $b$-hadron cross section down to zero transverse momentum at $\sqrt{s}=1960\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}$. We find the total single $b$-hadron cross section integrated over all transverse momenta for $b$ hadrons in the rapidity range $|y|l0.6$ to be $17.6\ifmmode\pm\else\textpm\fi{}0.4(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}{)}_{\ensuremath{-}2.3}^{+2.5}(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\text{ }\text{ }\ensuremath{\mu}\mathrm{b}$.

Measurement of the tt̄ production cross section in pp̄ collisions at √s = 1.96 TeV using lepton + jets events with secondary vertex b -tagging

Abstract: We present a measurement of the tt production cross section using events with one charged lepton and jets from pp collisions at a center-of-mass energy of 1.96 TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From 162 pb{sup -1} of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where 13.5{+-}1.8 events are expected from background contributions. We measure a tt production cross section of 5.6{sub -1.1}{sup +1.2}(stat.){sub -0.6}{sup +0.9}(syst.) pb.

Measurement of sin2β from B→J/ψKS0 with the CDF detector

Abstract: This paper reports an updated measurement of the standard model CP violation parameter sin 2{beta} using the CDF Detector at Fermilab. The entire run I data sample of 110 pb{sup -1} of proton-antiproton collisions at {radical}(s)=1.8 TeV is used to identify a signal sample of {approx}400 B{yields}J/{psi} K{sub S}{sup 0} events, where J/{psi}{yields}{mu}{sup +}{mu}{sup -} and K{sub S}{sup 0}{yields}{pi}{sup +}{pi}{sup -}. The flavor of the neutral B meson is identified at the time of production by combining information from three tagging algorithms: a same-side tag, a jet-charge tag, and a soft-lepton tag. A maximum likelihood fitting method is used to determine sin 2{beta}=0.79{sub -0.44}{sup +0.41}(stat+syst). This value of sin 2{beta} is consistent with the standard model prediction, based upon existing measurements, of a large positive CP-violating asymmetry in this decay mode. (c) 2000 The American Physical Society.

Upsilon production and polarization in p(p)over-bar collisions at root s=1.8 TeV

Abstract: We report on measurements of the Y(1S), Y(2S), and Y(3S) differential cross sections (d(2)sigma/dp(T)dy)(\y\ collisions at roots = 1.8 TeV using a sample of 77+/-3 pb(-1) collected by the collider detector at Fermilab. The three resonances were reconstructed through the decay Y-->mu(+)mu(-) . The measured angular distribution of the muons in the Y(1S) rest frame is consistent with unpolarized meson production.

New generation of parton distributions with uncertainties from global QCD analysis

Abstract: A new generation of parton distribution functions with increased precision and quantitative estimates of uncertainties is presented. This work signiflcantly extends previous CTEQ and other global analyses on two fronts: (i) a full treatment of available experimental correlated systematic errorsforbothnewandolddata sets; (ii) asystematic and pragmatic treatment of uncertainties of the parton distributions and their physical predictions, using a recently developed eigenvector-basis approach to the hessian method. The new gluon distribution is considerably harder than that of previous standard flts. A numberofphysicsissues,particularlyrelatingtothebehaviorofthegluondistribution,are addressedinmorequantitativetermsthanbefore. Extensiveresultsontheuncertaintiesof parton distributions at various scales, and on parton luminosity functions at the Tevatron RunII and the LHC, are presented. The latter provide the means to quickly estimate the uncertainties of a wide range of physical processes at these high-energy hadron colliders, basedoncurrentknowledgeofthepartondistributions. Inparticular, theuncertaintieson the production cross sections of the W, Z at the Tevatron and the LHC are estimated to be§4% and§5%, respectively, and that of a light Higgs at the LHC to be§5%.

Parton distributions for the LHC

Abstract: We present updated leading-order, next-to-leading order and next-to-next-to-leading order parton distribution functions (“MSTW 2008”) determined from global analysis of hard-scattering data within the standard framework of leading-twist fixed-order collinear factorisation in the $\overline{\mathrm{MS}}$ scheme. These parton distributions supersede the previously available “MRST” sets and should be used for the first LHC data taking and for the associated theoretical calculations. New data sets fitted include CCFR/NuTeV dimuon cross sections, which constrain the strange-quark and -antiquark distributions, and Tevatron Run II data on inclusive jet production, the lepton charge asymmetry from W decays and the Z rapidity distribution. Uncertainties are propagated from the experimental errors on the fitted data points using a new dynamic procedure for each eigenvector of the covariance matrix. We discuss the major changes compared to previous MRST fits, briefly compare to parton distributions obtained by other fitting groups, and give predictions for the W and Z total cross sections at the Tevatron and LHC.

The Cosmological Constant

Abstract: This is a review of the physics and cosmology of the cosmological constant. Focusing on recent developments, I present a pedagogical overview of cosmology in the presence of a cosmological constant, observational constraints on its magnitude, and the physics of a small (and potentially nonzero) vacuum energy.

Averages of b-hadron, c-hadron, and tau-lepton properties as of early 2012

Abstract: This article reports world averages of measurements of b-hadron, c-hadron, and tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through the end of 2011. In some cases results available in the early part of 2012 are included. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays and CKM matrix elements.