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Bross, Alan D

Publications and source records attributed to Bross, Alan D.

10 records
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DOE OSTI2017

Combination of D0 measurements of the top quark mass

We present a combination of measurements of the top quark mass by the D0 experiment in the lepton+jets and dilepton channels. We use all the data collected in Run I (1992–1996) at s=1.8 TeV and Run II (2001–2011) at s=1.96 TeV of the Tevatron pp¯ collider, corresponding to integrated luminosities of 0.1 fb-1 and 9.7 fb-1, respectively. The combined result is: mt=174.95±0.40(stat)±0.64(syst) GeV=174.95±0.75 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Measurement of the direct CP violating charge asymmetry in $B^\pm \rightarrow \mu^\pm \nu_\mu D^{0}$ decays

We present the first measurement of the CP violating charge asymmetry in B±→μ±νμD0 decays using the full Run II integrated luminosity of 10.4 fb-1 in proton-antiproton collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure a difference in the yield of B- and B+ mesons in these decays by fitting the reconstructed invariant mass distributions. This results in an asymmetry of AμD0=[-0.14±0.20]%, which is consistent with standard model predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Measurement of top quark polarization in t t ¯ lepton + jets final states

We present a measurement of top quark polarization in t ¯ t pair production in p ¯ p collisions at √ s = 1.96 TeV using data corresponding to 9.7 fb -1 of integrated luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. We consider final states containing a lepton and at least three jets. The polarization is measured through the distribution of lepton angles along three axes: the beam axis, the helicity axis, and the transverse axis normal to the t ¯ t production plane. This is the first measurement of top quark polarization at the Tevatron using lepton + jet final states and the first measurement of the transverse polarization in t ¯ t production. The observed distributions are consistent with standard model predictions of nearly no polarization.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Measurement of the Inclusive $t\bar{t}$ Production Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}=1.96$ TeV and Determination of the Top Quark Pole Mass

The inclusive cross section of top quark-antiquark pairs produced in pp¯ collisions at s=1.96 TeV is measured in the lepton+jets and dilepton decay channels. The data sample corresponds to 9.7 fb-1 of integrated luminosity recorded with the D0 detector during Run II of the Fermilab Tevatron Collider. Employing multivariate analysis techniques we measure the cross section in the two decay channels and we perform a combined cross section measurement. For a top quark mass of 172.5 GeV, we measure a combined inclusive top quark-antiquark pair production cross section of σtt¯=7.26±0.13(stat)-0.50+0.57(syst) pb which is consistent with standard model predictions. We also perform a likelihood fit to the measured and predicted top quark mass dependence of the inclusive cross section, which yields a measurement of the pole mass of the top quark. The extracted value is mt=172.8±1.1(theo)-3.1+3.3(exp) GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Measurement of the Top Quark Mass Using the Matrix Element Technique in Dilepton Final States

We present a measurement of the top quark mass in pp¯ collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. The data were collected by the D0 experiment corresponding to an integrated luminosity of 9.7 fb-1. The matrix element technique is applied to tt¯ events in the final state containing leptons (electrons or muons) with high transverse momenta and at least two jets. The calibration of the jet energy scale determined in the lepton+jets final state of tt¯ decays is applied to jet energies. This correction provides a substantial reduction in systematic uncertainties. We obtain a top quark mass of mt=173.93±1.84 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

$B^{0}_{s}$ lifetime measurement in the CP-odd decay channel $B^{0}_{s} \to J/\psi f_{0}(980)$

The lifetime of the Bs0 meson is measured in the decay channel Bs0→J/ψπ+π- with 880≤Mπ+π-≤1080 MeV/c2, which is mainly a CP-odd state and dominated by the f0(980) resonance. In 10.4 fb-1 of data collected with the D0 detector in Run II of the Tevatron, the lifetime of the Bs0 meson is measured to be τ(Bs0)=1.70±0.14(stat)±0.05(syst) ps. Neglecting CP violation in Bs0/B¯s0 mixing, the measurement can be translated into the width of the heavy mass eigenstate of the Bs0, ΓH=0.59±0.05(stat)±0.02(syst) ps-1.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Study of double parton interactions in diphoton + dijet events in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV

We use a sample of diphoton+dijet events to measure the effective cross section of double parton interactions, which characterizes the area containing the interacting partons in proton-antiproton collisions, and find it to be σeff=19.3±1.4(stat)±7.8(syst) mb. The sample was collected by the D0 detector at the Fermilab Tevatron collider in pp¯ collisions at s=1.96 TeV and corresponds to an integrated luminosity of 8.7 fb-1.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Measurement of the $B_s^0$ Lifetime in the Flavor-Specific Decay Channel $B_s^0 \to D_s^- \mu^+\nu X$

We present an updated measurement of the B s 0 lifetime using the semileptonic decays B s 0 → D s - μ + ν X , with D s - → ϕ π - and ϕ → K + K - (and the charge conjugate process). This measurement uses the full Tevatron Run II sample of proton-antiproton collisions at s = 1.96 TeV , comprising an integrated luminosity of 10.4 fb − 1 . We find a flavor-specific lifetime τ fs ( B s 0 ) = 1.479 ± 0.010 ( stat ) ± 0.021 ( syst ) ps . This technique is also used to determine the B 0 lifetime using the analogous B 0 → D - μ + ν X decay with D - → ϕ π - and ϕ → K + K - , yielding τ ( B 0 ) = 1.534 ± 0.019 ( stat ) ± 0.021 ( syst ) ps . Both measurements are consistent with the current world averages, and the B s 0 lifetime measurement is one of the most precise to date. Taking advantage of the cancellation of systematic uncertainties, we determine the lifetime ratio τ fs ( B s 0 ) / τ ( B 0 ) = 0.964 ± 0.013 ( stat ) ± 0.007 ( syst ) .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The US Muon Accelerator Program (MAP)

The US Department of Energy Office of High Energy Physics has recently approved a Muon Accelerator Program (MAP). The primary goal of this effort is to deliver a Design Feasibility Study for a Muon Collider after a 7 year R and D program. This paper presents a brief physics motivation for, and the description of, a Muon Collider facility and then gives an overview of the program. I will then describe in some detail the primary components of the effort.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗