D. M. Strom

Bio: D. M. Strom is an academic researcher from University of Oregon. The author has contributed to research in topics: Large Hadron Collider & Lepton. The author has an hindex of 176, co-authored 3167 publications receiving 194314 citations. Previous affiliations of D. M. Strom include University of Tokyo & University of Würzburg.

Measurement of BB̄ angular correlations based on secondary vertex reconstruction at √s = 7 TeV

Abstract: A measurement of the angular correlations between beauty and anti-beauty hadrons (B B-bar) produced in pp collisions at a centre-of-mass energy of 7 TeV at the CERN LHC is presented, probing for the first time the region of small angular separation. The B hadrons are identified by the presence of displaced secondary vertices from their decays. The B hadron angular separation is reconstructed from the decay vertices and the primary-interaction vertex. The differential B B-bar production cross section, measured from a data sample collected by CMS and corresponding to an integrated luminosity of 3.1 inverse picobarns, shows that a sizable fraction of the B B-bar pairs are produced with small opening angles. These studies provide a test of QCD and further insight into the dynamics of b b-bar production.

Prompt and non-prompt J/ψ and ψ (2S) suppression at high transverse momentum in 5.02 TeV Pb+Pb collisions with the ATLAS experiment

Abstract: A measurement of J/ψ and ψ(2S) production is presented. It is based on a data sample from Pb+Pb collisions at sNN−−−√=5.02 TeV and pp collisions at s√=5.02 TeV recorded by the ATLAS detector at the LHC in 2015, corresponding to an integrated luminosity of 0.42 nb−1 and 25 pb−1 in Pb+Pb and pp, respectively. The measurements of per-event yields, nuclear modification factors, and non-prompt fractions are performed in the dimuon decay channel for 9

Measurements of charged current lepton universality and |Vus| using tau lepton decays to e-ν̄eντ, μ -ν̄μντ, π-ντ, and K -ντ

Abstract: Using 467 fb(-1) of e+e- annihilation data collected with the BABAR detector, we measure (B(τ- → μ- ν(μ) ν(τ)))/(B(τ- → e- ν(e) ν(τ))) =(0.9796±0.0016±0.0036), (B(τ- → π- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.5945±0.0014±0.0061), and (B(τ- → K- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.03882±0.00032±0.00057), where the uncertainties are statistical and systematic, respectively. From these precision τ measurements, we test the standard model assumption of μ-e and τ-μ charge current lepton universality and provide determinations of |Vus| experimentally independent of the decay of a kaon.

Search for fractionally charged particles in pp collisions at s√=7 TeV

Abstract: A search is presented for free heavy long-lived fractionally charged particles produced in pp collisions at √s=7 TeV. The data sample was recorded by the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb-1. Candidate fractionally charged particles are identified by selecting tracks with associated low charge measurements in the silicon tracking detector. Observations are found to be consistent with expectations for background processes. The results of the search are used to set upper limits on the cross section for pair production of fractionally charged, massive spin-1/2 particles that are neutral under SU(3)C and SU(2)L. We exclude at 95% confidence level such particles with electric charge ±2e/3 with masses below 310 GeV, and those with charge ±e/3 with masses below 140 GeV.

Measurement of the t(t)over-bar production cross section, the top quark mass, and the strong coupling constant using dilepton events in pp collisions at root s=13TeV

Abstract: A measurement of the top quark–antiquark pair production cross section $\sigma _{\mathrm {t}\overline{\mathrm {t}}} $ in proton–proton collisions at a centre-of-mass energy of 13 $\,\text {Te}\text {V}$ is presented. The data correspond to an integrated luminosity of $35.9{\,\text {fb}^{-1}} $ , recorded by the CMS experiment at the CERN LHC in 2016. Dilepton events ( $\mathrm {e}^{\pm }$ $\mathrm {\mu }^{{\mp }}$ , $\mathrm {\mu ^+}\mathrm {\mu ^-}$ , $\mathrm {e}^+\mathrm {e}^-$ ) are selected and the cross section is measured from a likelihood fit. For a top quark mass parameter in the simulation of $ m_\mathrm {\mathrm {t}} ^{\mathrm {MC}} = 172.5 \,\text {Ge}\text {V} $ the fit yields a measured cross section $\sigma _{\mathrm {t}\overline{\mathrm {t}}} = 803 \pm 2 \,\text {(stat)} \pm 25 \,\text {(syst)} \pm 20 \,\text {(lumi)} \,\text {pb} $ , in agreement with the expectation from the standard model calculation at next-to-next-to-leading order. A simultaneous fit of the cross section and the top quark mass parameter in the powheg simulation is performed. The measured value of $m_\mathrm {\mathrm {t}} ^{\mathrm {MC}} = 172.33 \pm 0.14 \,\text {(stat)} \,^{+0.66-0.72} \,\text {(syst)} \,\text {Ge}\text {V} $ is in good agreement with previous measurements. The resulting cross section is used, together with the theoretical prediction, to determine the top quark mass and to extract a value of the strong coupling constant with different sets of parton distribution functions.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These