arXiv subjects

D. Cauz

Publications and source records attributed to D. Cauz.

At least 37 records · Page 2Linked to original sources

arXiv2021

Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre

We provide an updated assessment of the power of the Cherenkov Telescope Array (CTA) to search for thermally produced dark matter at the TeV scale, via the associated gamma-ray signal from pair-annihilating dark matter particles in the region around the Galactic centre. We find that CTA will open a new window of discovery potential, significantly extending the range of robustly testable models given a standard cuspy profile of the dark matter density distribution. Importantly, even for a cored profile, the projected sensitivity of CTA will be sufficient to probe various well-motivated models of thermally produced dark matter at the TeV scale. This is due to CTA's unprecedented sensitivity, angular and energy resolutions, and the planned observational strategy. The survey of the inner Galaxy will cover a much larger region than corresponding previous observational campaigns with imaging atmospheric Cherenkov telescopes. CTA will map with unprecedented precision the large-scale diffuse emission in high-energy gamma rays, constituting a background for dark matter searches for which we adopt state-of-the-art models based on current data. Throughout our analysis, we use up-to-date event reconstruction Monte Carlo tools developed by the CTA consortium, and pay special attention to quantifying the level of instrumental systematic uncertainties, as well as background template systematic errors, required to probe thermally produced dark matter at these energies. "Full likelihood tables complementing our analysis are provided here [ https://doi.org/10.5281/zenodo.4057987 ]"

astro-ph.HE↗

arXiv2021

A summary on an investigation of GAGG:Ce afterglow emission in the context of future space applications within the HERMES nanosatellite mission

GAGG:Ce (Cerium-doped Gadolinium Aluminium Gallium Garnet) is a promising new scintillator crystal. A wide array of interesting features, such as high light output, fast decay times, almost non-existent intrinsic background and robustness, make GAGG:Ce an interesting candidate as a component of new space-based gamma-ray detectors. As a consequence of its novelty, literature on GAGG:Ce is still lacking on points crucial to its applicability in space missions. In particular, GAGG:Ce is characterized by unusually high and long-lasting delayed luminescence. This afterglow emission can be stimulated by the interactions between the scintillator and the particles of the near-Earth radiation environment. By contributing to the noise, it will impact the detector performance to some degree. In this manuscript we summarize the results of an irradiation campaign of GAGG:Ce crystals with protons, conducted in the framework of the HERMES-TP/SP (High Energy Rapid Modular Ensemble of Satellites - Technological and Scientific Pathfinder) mission. A GAGG:Ce sample was irradiated with 70 MeV protons, at doses equivalent to those expected in equatorial and sun-synchronous Low-Earth orbits over orbital periods spanning 6 months to 10 years, time lapses representative of satellite lifetimes. We introduce a new model of GAGG:Ce afterglow emission able to fully capture our observations. Results are applied to the HERMES-TP/SP scenario, aiming at an upper-bound estimate of the detector performance degradation due to the afterglow emission expected from the interaction between the scintillator and the near-Earth radiation environment.

astro-ph.IM↗

arXiv2019

The laser-based gain monitoring system of the calorimeters in the Muon $g-2$ experiment at Fermilab

The Muon $g-2$ experiment, E989, is currently taking data at Fermilab with the aim of reducing the experimental error on the muon anomaly by a factor of four and possibly clarifying the current discrepancy with the theoretical prediction. A central component of this four-fold improvement in precision is the laser calibration system of the calorimeters, which has to monitor the gain variations of the photo-sensors with a 0.04\% precision on the short-term ($\sim 1\,$ms). This is about one order of magnitude better than what has ever been achieved for the calibration of a particle physics calorimeter. The system is designed to monitor also long-term gain variations, mostly due to temperature effects, with a precision below the per mille level. This article reviews the design, the implementation and the performance of the Muon $g-2$ laser calibration system, showing how the experimental requirements have been met.

physics.ins-det↗

arXiv2019

Monte Carlo studies for the optimisation of the Cherenkov Telescope Array layout

The Cherenkov Telescope Array (CTA) is the major next-generation observatory for ground-based very-high-energy gamma-ray astronomy. It will improve the sensitivity of current ground-based instruments by a factor of five to twenty, depending on the energy, greatly improving both their angular and energy resolutions over four decades in energy (from 20 GeV to 300 TeV). This achievement will be possible by using tens of imaging Cherenkov telescopes of three successive sizes. They will be arranged into two arrays, one per hemisphere, located on the La Palma island (Spain) and in Paranal (Chile). We present here the optimised and final telescope arrays for both CTA sites, as well as their foreseen performance, resulting from the analysis of three different large-scale Monte Carlo productions.

astro-ph.IM↗

arXiv2019

Search for Higgs-like particles produced in association with bottom quarks in proton-antiproton collisions

We report on a search for a spin-zero non-standard-model particle in proton-antiproton collisions collected by the Collider Detector at Fermilab at a center-of-mass-energy of 1.96 TeV. This particle, the $ϕ$ boson, is expected to decay into a bottom-antibottom quark pair and to be produced in association with at least one bottom quark. The data sample consists of events with three jets identified as initiated by bottom quarks and corresponds to $5.4~\text{fb}^{-1}$ of integrated luminosity. In each event, the invariant mass of the two most energetic jets is studied by looking for deviations from the multijet background, which is modeled using data. No evidence is found for such particle. Exclusion upper limits ranging from 20 to 2 pb are set for the product of production cross sections times branching fraction for hypothetical $ϕ$ boson with mass between 100 and 300 GeV/$c^2$. These are the most stringent constraints to date.

hep-ex↗

arXiv2018

HERMES: An ultra-wide band X and gamma-ray transient monitor on board a nano-satellite constellation

The High Energy Modular Ensemble of Satellites (HERMES) project is aimed to realize a modular X/gamma-ray monitor for transient events, to be placed on-board of a CubeSat bus. This expandable platform will achieve a significant impact on Gamma Ray Burst (GRB) science and on the detection of Gravitational Wave (GW) electromagnetic counterparts: the recent LIGO/VIRGO discoveries demonstrated that the high-energy transient sky is still a field of extreme interest. The very complex temporal variability of GRBs (up to the millisecond scale) combined with the spatial and temporal coincidence between GWs and their electromagnetic counterparts suggest that upcoming instruments require sub-ms time resolution combined with a transient localization accuracy lower than a degree. The current phase of the ongoing HERMES project is focused on the realization of a technological pathfinder with a small network (3 units) of nano-satellites to be launched in mid 2020. We will show the potential and prospects for short and medium-term development of the project, demonstrating the disrupting possibilities for scientific investigations provided by the innovative concept of a new "modular astronomy" with nano-satellites (e.g. low developing costs, very short realization time). Finally, we will illustrate the characteristics of the HERMES Technological Pathfinder project, demonstrating how the scientific goals discussed are actually already reachable with the first nano-satellites of this constellation. The detector architecture will be described in detail, showing that the new generation of scintillators (e.g. GAGG:Ce) coupled with very performing Silicon Drift Detectors (SDD) and low noise Front-End-Electronics (FEE) are able to extend down to few keV the sensitivity band of the detector. The technical solutions for FEE, Back-End-Electronics (BEE) and Data Handling will be also described.

astro-ph.IM↗

arXiv2018

Search for standard-model Z and Higgs bosons decaying into a bottom-antibottom quark pair in proton-antiproton collisions at 1.96 TeV

The Collider Detector at Fermilab collected a unique sample of jets originating from bottom-quark fragmentation ($b$-jets) by selecting online proton-antiproton ($p\bar{p}$) collisions with a vertex displaced from the $p\bar{p}$ interaction point, consistent with the decay of a bottom-quark hadron. This data set, collected at a center-of-mass energy of $\sqrt{s}=$1.96 TeV, and corresponding to an integrated luminosity of $5.4~\rm{fb}^{-1}$, is used to measure the $Z$-boson production cross section times branching ratio into $b\bar{b}$. The number of $Z\rightarrow b\bar{b}$ events is determined by fitting the dijet-mass distribution while constraining the dominant $b$-jet background, originating from QCD multijet events, with data. The result, $σ(p\bar{p} \rightarrow Z) \times \mathcal{B}(Z \rightarrow b\bar{b})= 1.11\pm 0.08(\text{stat}) \pm 0.14(\text{syst})~\text{nb}$, is the most precise measurement of this process, and is consistent with the standard-model prediction. The data set is also used to search for Higgs-boson production. No significant signal is expected in our data and the first upper limit on the cross section for the inclusive $p\bar p \rightarrow H\rightarrow b\bar b$ process at $\sqrt{s}=$1.96 TeV is set, corresponding to 33 times the expected standard-model cross section, or $σ= 40.6$ pb, at the 95\% confidence level.

hep-ex↗

arXiv2018

Measurement of the differential cross sections for $W$-boson production in association with jets in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

This paper presents a study of the production of a single $W$ boson in association with one or more jets in proton-antiproton collisions at $\sqrt{s}=1.96$ TeV, using the entire data set collected in 2001-2011 by the Collider Detector at Fermilab at the Tevatron, which corresponds to an integrated luminosity of $9.0$ fb$^{-1}$. The $W$ boson is identified through its leptonic decays into electron and muon. The production cross sections are measured for each leptonic decay mode and combined after testing that the ratio of the $W(\rightarrow μν)+$jets cross section to the $W(\rightarrow eν)+$jets cross section agrees with the hypothesis of $e$-$μ$ lepton universality. The combination of measured cross sections, differential in the inclusive jet multiplicity ($W+\geqslant N$ jets with $N=1,\,2,\,3, \textrm{or }4$) and in the transverse energy of the leading jet, are compared with theoretical predictions.

hep-ex↗

arXiv2018

Science with the Cherenkov Telescope Array

The Cherenkov Telescope Array, CTA, will be the major global observatory for very high energy gamma-ray astronomy over the next decade and beyond. The scientific potential of CTA is extremely broad: from understanding the role of relativistic cosmic particles to the search for dark matter. CTA is an explorer of the extreme universe, probing environments from the immediate neighbourhood of black holes to cosmic voids on the largest scales. Covering a huge range in photon energy from 20 GeV to 300 TeV, CTA will improve on all aspects of performance with respect to current instruments. The observatory will operate arrays on sites in both hemispheres to provide full sky coverage and will hence maximize the potential for the rarest phenomena such as very nearby supernovae, gamma-ray bursts or gravitational wave transients. With 99 telescopes on the southern site and 19 telescopes on the northern site, flexible operation will be possible, with sub-arrays available for specific tasks. CTA will have important synergies with many of the new generation of major astronomical and astroparticle observatories. Multi-wavelength and multi-messenger approaches combining CTA data with those from other instruments will lead to a deeper understanding of the broad-band non-thermal properties of target sources. The CTA Observatory will be operated as an open, proposal-driven observatory, with all data available on a public archive after a pre-defined proprietary period. Scientists from institutions worldwide have combined together to form the CTA Consortium. This Consortium has prepared a proposal for a Core Programme of highly motivated observations. The programme, encompassing approximately 40% of the available observing time over the first ten years of CTA operation, is made up of individual Key Science Projects (KSPs), which are presented in this document.

astro-ph.IM↗

arXiv2017

A search for the exotic meson $X(5568)$ with the Collider Detector at Fermilab

A search for the exotic meson $X(5568)$ decaying into the $B^0_s π^{\pm}$ final state is performed using data corresponding to $9.6 \textrm{fb}^{-1}$ from $p{\bar p}$ collisions at $\sqrt{s} = 1960$ GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7\% at the 95\% confidence level is set on the fraction of $B^0_s$ produced through the $X(5568) \rightarrow B^0_s \, π^{\pm}$ process.

hep-ex↗

arXiv2017

Measurement of the inclusive-isolated prompt-photon cross section in $p\bar{p}$ collisions using the full CDF data set

A measurement of the inclusive production cross section of isolated prompt photons in proton-antiproton collisions at center-of-mass energy $\sqrt{s}$=1.96TeV is presented. The results are obtained using the full Run II data sample collected with the Collider Detector at the Fermilab Tevatron, which corresponds to an integrated luminosity of 9.5fb$^{-1}$. The cross section is measured as a function of photon transverse energy, $E_T^γ$, in the range 30$ < E_T^γ <$500GeV and in the pseudorapidity region $|η^γ|<$1.0. The results are compared with predictions from parton-shower Monte Carlo models at leading order in quantum chromodynamics (QCD) and from next-to-leading order perturbative QCD calculations. The latter show good agreement with the measured cross section.

hep-ex↗

arXiv2016

Measurement of the $D^+$-meson production cross section at low transverse momentum in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

We report on a measurement of the $D^{+}$-meson production cross section as a function of transverse momentum ($p_T$) in proton-antiproton ($p\bar{p}$) collisions at 1.96 TeV center-of-mass energy, using the full data set collected by the Collider Detector at Fermilab in Tevatron Run II and corresponding to 10 fb$^{-1}$ of integrated luminosity. We use $D^{+} \to K^-π^+π^+$ decays fully reconstructed in the central rapidity region $|y|<1$ with transverse momentum down to 1.5 GeV/$c$, a range previously unexplored in $p\bar{p}$ collisions. Inelastic $p\bar{p}$-scattering events are selected online using minimally-biasing requirements followed by an optimized offline selection. The $K^-π^+π^+$ mass distribution is used to identify the $D^+$ signal, and the $D^+$ transverse impact-parameter distribution is used to separate prompt production, occurring directly in the hard scattering process, from secondary production from $b$-hadron decays. We obtain a prompt $D^+$ signal of 2950 candidates corresponding to a total cross section $σ(D^+, 1.5 < p_T < 14.5~\mbox{GeV/}c, |y|<1) = 71.9 \pm 6.8 (\mbox{stat}) \pm 9.3 (\mbox{syst})~μ$b. While the measured cross sections are consistent with theoretical estimates in each $p_T$ bin, the shape of the observed $p_T$ spectrum is softer than the expectation from quantum chromodynamics. The results are unique in $p\bar{p}$ collisions and can improve the shape and uncertainties of future predictions.

hep-ex↗

arXiv2016

Electron beam test of key elements of the laser-based calibration system for the muon $g$ $-$ $2$ experiment

We report the test of many of the key elements of the laser-based calibration system for muon g - 2 experiment E989 at Fermilab. The test was performed at the Laboratori Nazionali di Frascati's Beam Test Facility using a 450 MeV electron beam impinging on a small subset of the final g - 2 lead-fluoride crystal calorimeter system. The calibration system was configured as planned for the E989 experiment and uses the same type of laser and most of the final optical elements. We show results regarding the calorimeter's response calibration, the maximum equivalent electron energy which can be provided by the laser and the stability of the calibration system components.

physics.ins-det↗

arXiv2016

Measurement of the $WW$ and $WZ$ production cross section using final states with a charged lepton and heavy-flavor jets in the full CDF Run II data set

We present a measurement of the total {\it WW} and {\it WZ} production cross sections in $p\bar{p}$ collision at $\sqrt{s}=1.96$ TeV, in a final state consistent with leptonic $W$ boson decay and jets originating from heavy-flavor quarks from either a $W$ or a $Z$ boson decay. This analysis uses the full data set collected with the CDF II detector during Run II of the Tevatron collider, corresponding to an integrated luminosity of 9.4 fb$^{-1}$. An analysis of the dijet mass spectrum provides $3.7σ$ evidence of the summed production processes of either {\it WW} or {\it WZ} bosons with a measured total cross section of $σ_{WW+WZ} = 13.7\pm 3.9$~pb. Independent measurements of the {\it WW} and {\it WZ} production cross sections are allowed by the different heavy-flavor decay-patterns of the $W$ and $Z$ bosons and by the analysis of secondary-decay vertices reconstructed within heavy-flavor jets. The productions of {\it WW} and of {\it WZ} dibosons are independently seen with significances of $2.9σ$ and $2.1σ$, respectively, with total cross sections of $σ_{WW}= 9.4\pm 4.2$~pb and $σ_{WZ}=3.7^{+2.5}_{-2.2}$~pb. The measurements are consistent with standard-model predictions.

hep-ex↗

arXiv2016

Measurement of $\sin^2θ^{\rm lept}_{\rm eff}$ using $e^+e^-$ pairs from $γ^*/Z$ bosons produced in $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV

At the Fermilab Tevatron proton-antiproton ($p\bar{p}$) collider, Drell-Yan lepton pairs are produced in the process $p \bar{p} \rightarrow e^+e^- + X$ through an intermediate $γ^*/Z$ boson. The forward-backward asymmetry in the polar-angle distribution of the $e^-$ as a function of the $e^+e^-$-pair mass is used to obtain $\sin^2θ^{\rm lept}_{\rm eff}$, the effective leptonic determination of the electroweak-mixing parameter $\sin^2θ_W$. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.4~fb$^{-1}$ of integrated luminosity from $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of $\sin^2θ^{\rm lept}_{\rm eff}$ is found to be $0.23248 \pm 0.00053$. The combination with the previous CDF measurement based on $μ^+μ^-$ pairs yields $\sin^2θ^{\rm lept}_{\rm eff} = 0.23221 \pm 0.00046$. This result, when interpreted within the specified context of the standard model assuming $\sin^2 θ_W = 1 - M_W^2/M_Z^2$ and that the $W$- and $Z$-boson masses are on-shell, yields $\sin^2θ_W = 0.22400 \pm 0.00045$, or equivalently a $W$-boson mass of $80.328 \pm 0.024 \;{\rm GeV}/c^2$.

hep-ex↗

arXiv2016

Measurement of the $B_c^{\pm}$ production cross section in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

We describe a measurement of the ratio of the cross sections times branching fractions of the $B_c^+$ meson in the decay mode $B_c^+ \rightarrow J/ψμν$ to the $B^+$ meson in the decay mode $B^+ \rightarrow J/ψK^+$ in proton-antiproton collisions at center-of-mass energy $\sqrt{s}=1.96$ TeV. The measurement is based on the complete CDF Run II data set, which comes from an integrated luminosity of $8.7\,{\rm fb}^{-1}$. The ratio of the production cross sections times branching fractions for $B_c^+$ and $B_c^+$ mesons with momentum transverse to the beam greater than $6~\textrm{GeV}/c$ and rapidity magnitude smaller than 0.6 is $0.211\pm 0.012~\mbox{(stat)}^{+0.021}_{-0.020}~\mbox{(syst)}$. Using the known $B^+ \rightarrow J/ψK^+$ branching fraction, the known $B^+$ production cross section, and a selection of the predicted $B_c^+ \rightarrow J/ψμν$ branching fractions, the range for the total $B_c^+$ production cross section is estimated.

hep-ex↗

arXiv2016

Measurement of vector boson plus $D^{*}(2010)^+$ meson production in $\bar{p}p$ collisions at $\sqrt{s}=1.96\, {\rm TeV}$

A measurement of vector boson ($V$) production in conjunction with a $D^{*}(2010)^+$ meson is presented. Using a data sample corresponding to $9.7\, {\rm fb}^{-1}$ of ^Mproton-antiproton collisions at center-of-mass energy $\sqrt{s}=1.96\rm~ TeV$ produced by the Fermilab Tevatron, we reconstruct $V+D^{*+}$ samples with the CDF~II detector. The $D^{*+}$ is fully reconstructed in the $D^{*}(2010)^+ \rightarrow D^{0}(\to K^-π^+)π^+$ decay mode. This technique is sensitive to the associated production of vector boson plus charm or bottom mesons. We measure the ratio of production cross sections $σ(W+D^{*})/σ(W)$ = $[1.75\pm 0.13 {\rm (stat)}\pm 0.09 {\rm (syst)}]\% $ and $σ(Z+D^{*})/σ(Z)$ = $[1.5\pm 0.4 {\rm (stat)} \pm 0.2 {\rm (syst)}]\% $ and perform a differential measurement of $dσ(W+D^{*})/dp_T(D^{*})$. Event properties are utilized to determine the fraction of $V+D^{*}(2010)^+$ events originating from different production processes. The results are in agreement with the predictions obtained with the {\sc pythia} program, limiting possible contribution from non-standard-model physics processes.

hep-ex↗

arXiv2016

Measurement of the forward-backward asymmetry of top-quark and antiquark pairs using the full CDF Run II data set

We measure the forward--backward asymmetry of the production of top quark and antiquark pairs in proton-antiproton collisions at center-of-mass energy $\sqrt{s} = 1.96~\mathrm{TeV}$ using the full data set collected by the Collider Detector at Fermilab (CDF) in Tevatron Run II corresponding to an integrated luminosity of $9.1~\rm{fb}^{-1}$. The asymmetry is characterized by the rapidity difference between top quarks and antiquarks ($Δy$), and measured in the final state with two charged leptons (electrons and muons). The inclusive asymmetry, corrected to the entire phase space at parton level, is measured to be $A_{\text{FB}}^{t\bar{t}} = 0.12 \pm 0.13$, consistent with the expectations from the standard-model (SM) and previous CDF results in the final state with a single charged lepton. The combination of the CDF measurements of the inclusive $A_{\text{FB}}^{t\bar{t}}$ in both final states yields $A_{\text{FB}}^{t\bar{t}}=0.160\pm0.045$, which is consistent with the SM predictions. We also measure the differential asymmetry as a function of $Δy$. A linear fit to $A_{\text{FB}}^{t\bar{t}}(|Δy|)$, assuming zero asymmetry at $Δy=0$, yields a slope of $α=0.14\pm0.15$, consistent with the SM prediction and the previous CDF determination in the final state with a single charged lepton. The combined slope of $A_{\text{FB}}^{t\bar{t}}(|Δy|)$ in the two final states is $α=0.227\pm0.057$, which is $2.0σ$ larger than the SM prediction.

hep-ex↗