German Martinez

Bio: German Martinez is an academic researcher from Florida State University. The author has contributed to research in topics: Large Hadron Collider & Lepton. The author has an hindex of 141, co-authored 1476 publications receiving 107887 citations. Previous affiliations of German Martinez include University of Maryland, College Park & École des mines de Nantes.

Measurement of the t t ¯ production cross section using events with one lepton and at least one jet in pp collisions at √s=13 TeV

Abstract: A measurement of the tt production cross section at √s = 13 TeV is presented using proton-proton collisions, corresponding to an integrated luminosity of 2.2 fb^(−1), collected with the CMS detector at the LHC. Final states with one isolated charged lepton (electron or muon) and at least one jet are selected and categorized according to the accompanying jet multiplicity. From a likelihood fit to the invariant mass distribution of the isolated lepton and a jet identified as coming from the hadronization of a bottom quark, the cross section is measured to be σ_(tt) = 888 ± 2,(stat)^(+26)_(−28)(syst)±20(lumi)pb, in agreement with the standard model prediction. Using the expected dependence of the cross section on the pole mass of the top quark (m_t), the value of m_t is found to be 170.6 ± 2.7 GeV.

Measurement of associated production of a W boson and a charm quark in proton-proton collisions at s=13Te.

Abstract: Measurements are presented of associated production of a $\mathrm {W}$ boson and a charm quark ( $\mathrm {W}+\mathrm {c}$ ) in proton–proton collisions at a center-of-mass energy of 13 $\,\text {Te}\text {V}$ . The data correspond to an integrated luminosity of 35.7 $\,\text {fb}^{-1}$ collected by the CMS experiment at the CERN LHC. The $\mathrm {W}$ bosons are identified by their decay into a muon and a neutrino. The charm quarks are tagged via the full reconstruction of ${\mathrm {D}^{*}(2010)^{\pm }}$ mesons that decay via ${\mathrm {D}^{*}(2010)^{\pm }}\rightarrow \mathrm {D}^0 + {\pi ^{\pm }}\rightarrow \mathrm {K}^{\mp } + {\pi ^{\pm }}+ {\pi ^{\pm }}$ . A cross section is measured in the fiducial region defined by the muon transverse momentum $p_{\mathrm {T}} ^{\mu } > 26\,\text {Ge}\text {V} $ , muon pseudorapidity $|\eta ^{\mu } | 5\,\text {Ge}\text {V} $ . The inclusive cross section for this kinematic range is $\sigma (\mathrm {W}+\mathrm {c})=1026\pm 31\,\text {(stat)} \begin{array}{c} +76\\ -72 \end{array}\,\text {(syst)} \text { pb} $ . The cross section is also measured differentially as a function of the pseudorapidity of the muon from the $\mathrm {W}$ boson decay. These measurements are compared with theoretical predictions and are used to probe the strange quark content of the proton.

Factors associated with pathways toward concurrent sex work and injection drug use among female sex workers who inject drugs in northern Mexico.

Abstract: Aims To identify factors associated with time to initiation of (i) sex work prior to injecting drugs initiation; (ii) injection drug use prior to sex work initiation; and (iii) concurrent sex work and injection drug use (i.e. initiated at the same age) among female sex workers who currently inject drugs (FSW-IDU).Design Parametric survival analysis of baseline data for time to initiation event. Setting Tijuana and Ciudad Juarez situated on the Mexico-US border. Participants A total of 557 FSW-IDUs aged 18 years. Measurements Interview-administered surveys assessing context of sex work and injection drug use initiation. Findings Nearly half (n = 258) initiated sex work prior to beginning to inject, a third (n = 163) initiated injection first and a quarter (n = 136) initiated both sex work and injection drug use concurrently. Low education and living in Ciudad Juarez accelerated time to sex work initiation. Being from a southern Mexican state and initiating drug use with inhalants delayed the time to first injection drug use. Having an intimate partner encourage entry into sex work and first injecting drugs to deal with depression accelerated time to initiating sex work and injection concurrently. Early physical abuse accelerated time to initiating sex work and injection, and substantially accelerated time to initiation of both behaviors concurrently.Conclusions Among female sex workers who currently inject drugs in two Mexican-US border cities, nearly half appear to initiate sex work prior to beginning to inject, nearly one-third initiate injection drug use before beginning sex work and one-quarter initiate both behaviors concurrently. Predictors of these three trajectories differ, and this provides possible modifiable targets for

Search for heavy resonances that decay into a vector boson and a Higgs boson in hadronic final states at root s=13TeV

Abstract: A search for heavy resonances with masses above 1 TeV, decaying to final states containing a vector boson and a Higgs boson, is presented. The search considers hadronic decays of the vector boson, and Higgs boson decays to b quarks. The decay products are highly boosted, and each collimated pair of quarks is reconstructed as a single, massive jet. The analysis is performed using a data sample collected in 2016 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1). The data are consistent with the background expectation and are used to place limits on the parameters of a theoretical model with a heavy vector triplet. In the benchmark scenario with mass-degenerate W' and Z' bosons decaying predominantly to pairs of standard model bosons, for the first time heavy resonances for masses as high as 3.3 TeV are excluded at 95% confidence level, setting the most stringent constraints to date on such states decaying into a vector boson and a Higgs boson.

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 …

Planck 2015 results - XIII. Cosmological parameters

Abstract: This paper presents cosmological results based on full-mission Planck observations of temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation. Our results are in very good agreement with the 2013 analysis of the Planck nominal-mission temperature data, but with increased precision. The temperature and polarization power spectra are consistent with the standard spatially-flat 6-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations (denoted “base ΛCDM” in this paper). From the Planck temperature data combined with Planck lensing, for this cosmology we find a Hubble constant, H0 = (67.8 ± 0.9) km s-1Mpc-1, a matter density parameter Ωm = 0.308 ± 0.012, and a tilted scalar spectral index with ns = 0.968 ± 0.006, consistent with the 2013 analysis. Note that in this abstract we quote 68% confidence limits on measured parameters and 95% upper limits on other parameters. We present the first results of polarization measurements with the Low Frequency Instrument at large angular scales. Combined with the Planck temperature and lensing data, these measurements give a reionization optical depth of τ = 0.066 ± 0.016, corresponding to a reionization redshift of . These results are consistent with those from WMAP polarization measurements cleaned for dust emission using 353-GHz polarization maps from the High Frequency Instrument. We find no evidence for any departure from base ΛCDM in the neutrino sector of the theory; for example, combining Planck observations with other astrophysical data we find Neff = 3.15 ± 0.23 for the effective number of relativistic degrees of freedom, consistent with the value Neff = 3.046 of the Standard Model of particle physics. The sum of neutrino masses is constrained to ∑ mν < 0.23 eV. The spatial curvature of our Universe is found to be very close to zero, with | ΩK | < 0.005. Adding a tensor component as a single-parameter extension to base ΛCDM we find an upper limit on the tensor-to-scalar ratio of r0.002< 0.11, consistent with the Planck 2013 results and consistent with the B-mode polarization constraints from a joint analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP B-mode data to our analysis leads to a tighter constraint of r0.002 < 0.09 and disfavours inflationarymodels with a V(φ) ∝ φ2 potential. The addition of Planck polarization data leads to strong constraints on deviations from a purely adiabatic spectrum of fluctuations. We find no evidence for any contribution from isocurvature perturbations or from cosmic defects. Combining Planck data with other astrophysical data, including Type Ia supernovae, the equation of state of dark energy is constrained to w = −1.006 ± 0.045, consistent with the expected value for a cosmological constant. The standard big bang nucleosynthesis predictions for the helium and deuterium abundances for the best-fit Planck base ΛCDM cosmology are in excellent agreement with observations. We also constraints on annihilating dark matter and on possible deviations from the standard recombination history. In neither case do we find no evidence for new physics. The Planck results for base ΛCDM are in good agreement with baryon acoustic oscillation data and with the JLA sample of Type Ia supernovae. However, as in the 2013 analysis, the amplitude of the fluctuation spectrum is found to be higher than inferred from some analyses of rich cluster counts and weak gravitational lensing. We show that these tensions cannot easily be resolved with simple modifications of the base ΛCDM cosmology. Apart from these tensions, the base ΛCDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets.

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