About

Verena Martinez Outschoorn is a professor in the Department of Physics at the University of Massachusetts Amherst. She received her bachelor's degree in physics and mathematics in 2005 and her Ph.D. in physics in 2011 from Harvard University. Following her doctoral studies, she was a Lederman Postdoctoral Fellow at Fermi National Laboratory from 2011 to 2014. She then served as an Assistant Professor at the University of Illinois Urbana-Champaign from 2014 to 2017 before joining the Physics department at UMass Amherst in 2017. Her research focuses on experimental high energy physics, particularly at the Large Hadron Collider (LHC) at CERN. She is a member of the ATLAS Collaboration and has previously been part of the CMS Collaboration. Her work involves searching for new physics phenomena, including using the Higgs boson to look for potential dark matter particles and exploring explanations for the light mass of the Higgs boson, such as additional scalar particles or top partners. She is actively involved in improving the capabilities of the ATLAS experiment, especially the muon detectors, by designing and constructing upgrades to enhance detection and data collection. Her contributions aim to better understand fundamental questions in particle physics, astrophysics, and cosmology.

Research topics

• Physics
• Particle physics
• Nuclear physics
• Computer Science
• Optics
• Geology
• Quantum mechanics
• Biology
• Telecommunications
• Computer hardware
• Operating system
• Astrophysics
• Real-time computing

Selected publications

• A simplified configuration for common algorithms for ATLAS analysis

  EPJ Web of Conferences · 2025-01-01

  articleOpen accessSenior author

  In the ATLAS analysis model, users interact with specialized algorithms to perform a variety of tasks on their physics objects including calibration, identification, and obtaining systematic uncertainties for simulated events. These algorithms have a wide variety of configurations, and often must be applied in specific orders. A user-friendly configuration mechanism has been developed with the goal of improving the user experience from the perspective of both ease-of-use and stability. Users can now configure necessary algorithms via a YAML file, enabled by a physics-oriented python configuration. The configuration mechanism and training are discussed.§

  PublisherOA PDFDOI

• ATLAS Data Analysis using a Parallel Workflow on Distributed Cloud-based Services with GPUs

  EPJ Web of Conferences · 2024-01-01 · 2 citations

  articleOpen access

  A new type of parallel workflow is developed for the ATLAS experiment at the Large Hadron Collider, that makes use of distributed computing combined with a cloud-based infrastructure. This has been developed for a specific type of analysis using ATLAS data, one popularly referred to as Simulation-Based Inference (SBI). The JAX library is used for the parts of the workflow to compute gradients as well as accelerate program execution using just-in-time compilation, which becomes essential in a full SBI analysis and can also offer significant speed-ups in more traditional types of analysis.

  PublisherOA PDFDOI

• Operational experience and R&D results using the Google Cloud for High-Energy Physics in the ATLAS experiment

  International Journal of Modern Physics A · 2024-05-20 · 6 citations

  preprintOpen access

  The ATLAS experiment at CERN relies on a Worldwide Distributed Computing Grid infrastructure to support its physics program at the Large Hadron Collider. ATLAS has integrated cloud computing resources to complement its Grid infrastructure and conducted an R&D program on Google Cloud Platform. These initiatives leverage key features of commercial cloud providers: lightweight configuration and operation, elasticity and availability of diverse infrastructures. This paper examines the seamless integration of cloud computing services as a conventional Grid site within the ATLAS workflow management and data management systems, while also offering new setups for interactive, parallel analysis. It underscores pivotal results that enhance the on-site computing model and outlines several R&D projects that have benefited from large-scale, elastic resource provisioning models. Furthermore, this study discusses the impact of cloud-enabled R&D projects in three domains: accelerators and AI/ML, ARM CPUs and columnar data analysis techniques.

  PublisherDOI

• Exotic Higgs Decays

  Annual Review of Nuclear and Particle Science · 2022-06-27

  articleOpen access

  Exotic decays of the Standard Model (SM)-like Higgs boson into beyond-the-SM particles are predicted in a wide range of well-motivated theories. The enormous samples of Higgs bosons that have been and will be produced at the Large Hadron Collider thus constitute one of the key discovery opportunities at that facility, particularly in the upcoming high-statistics, high-luminosity run. Here we review recent theoretical work on models that predict or accommodate exotic Higgs decays, survey the status of current experimental searches, and look forward to future capabilities at dedicated Higgs factories and beyond.

  PublisherDOI

• Search for heavy Higgs bosons decaying into two tau leptons with the ATLAS detector using pp collisions at $\sqrt(s)$ = 13 TeV

  Proceedings of The European Physical Society Conference on High Energy Physics — PoS(EPS-HEP2021) · 2022 · 1 citations

  • Physics
  • Particle physics
  • Nuclear physics

  A search for heavy neutral Higgs bosons is performed using the LHC Run 2 data, corresponding to an integrated luminosity of 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}=13$ TeV recorded by the ATLAS detector. The heavy resonance search is performed over the mass range 0.2-2.5~TeV for the $\tau^{+}\tau^{-}$ decay with at least one $\tau$-lepton decaying into handronic final states. The data is in good agreement with the standard model predictions. Results are interpreted in terms of several Minimum Supersymmetry Standard Model scenarios.

  DOI

• Test of the universality of $\tau$ and $\mu$ lepton couplings in $W$-boson decays from $t\bar{t}$ events with the ATLAS detector

  2020 · 3 citations

  • Physics
  • Particle physics
  • Nuclear physics

  The Standard Model of particle physics encapsulates our current best understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the electroweak gauge bosons. The measurement of the ratio of the rate of decay of $W$ bosons to $\tau$-leptons and muons, $R(\tau/\mu) = B(W \to \tau \nu_\tau)/B(W \to \mu \nu_\mu)$, constitutes an important test of this axiom. A measurement of this quantity with a novel technique using di-leptonic $t\bar{t}$ events is presented based on 139 fb${}^{-1}$ of data recorded with the ATLAS detector in proton--proton collisions at $\sqrt{s}=13$ TeV. Muons originating from $W$ bosons and those originating from an intermediate $\tau$-lepton are distinguished using the lifetime of the $\tau$-lepton, through the muon transverse impact parameter, and differences in the muon transverse momentum spectra. The value of $R(\tau/\mu)$ is found to be $0.992 \pm 0.013 [\pm 0.007 (stat) \pm 0.011 (syst)]$ and is in agreement with the hypothesis of universal lepton couplings as postulated in the Standard Model. This is the most precise measurement of this ratio, and the only such measurement from the Large Hadron Collider, to date.

  PublisherOA PDF

• Observation of electroweak production of two jets and a $Z$-boson pair with the ATLAS detector at the LHC

  HAL (Le Centre pour la Communication Scientifique Directe) · 2020 · 16 citations

  • Physics
  • Particle physics
  • Nuclear physics

  Electroweak symmetry breaking explains the origin of the masses of elementary particles through their interactions with the Higgs field. Besides the measurements of the Higgs boson properties, the study of the scattering of massive vector bosons with spin 1 allows the nature of electroweak symmetry breaking to be probed. Among all processes related to vector-boson scattering, the electroweak production of two jets and a Z-boson pair is a rare and important one. Here we report the observation of this process from proton–proton collision data corresponding to an integrated luminosity of 139 fb$^{−1}$ recorded at a centre-of-mass energy of 13 TeV with the ATLAS detector at the Large Hadron Collider. We consider two different final states originating from the decays of the Z-boson pair: one containing four charged leptons and another containing two charged leptons and two neutrinos. The hypothesis of no electroweak production is rejected with a statistical significance of 5.7σ, and the measured cross-section for electroweak production is consistent with the Standard Model prediction. In addition, we report cross-sections for inclusive production of a Z-boson pair and two jets for the two final states.

• Operation of the ATLAS trigger system in Run 2

  Journal of Instrumentation · 2020 · 115 citations

  • Computer Science
  • Computer Science
  • Physics

  :

  DOI

• Search for dijet resonances in events with an isolated charged lepton using $\sqrt{s} = 13$ TeV proton-proton collision data collected by the ATLAS detector

  Desy Publications Database (Deutsches Elektronen-Synchrotron DESY) · 2020

  • Computer Science
  • Physics
  • Particle physics

  A search for dijet resonances in events with at least one isolated charged lepton is performed using $139~{\text{fb}}^{-1}$ of $\sqrt{s}=13$ TeV proton-proton collision data recorded by the ATLAS detector at the LHC. The dijet invariant-mass ($m_{jj}$) distribution constructed from events with at least one isolated electron or muon is searched in the region $0.22 < m_{jj} < 6.3$ TeV for excesses above a smoothly falling background from Standard Model processes. Triggering based on the presence of a lepton in the event reduces limitations imposed by minimum transverse momentum thresholds for triggering on jets. This approach allows smaller dijet invariant masses to be probed than in inclusive dijet searches, targeting a variety of new-physics models, for example ones in which a new state is produced in association with a leptonically decaying $W$ or $Z$ boson. No statistically significant deviation from the Standard Model background hypothesis is found. Limits on contributions from generic Gaussian signals with widths ranging from that determined by the detector resolution up to 15% of the resonance mass are obtained for dijet invariant masses ranging from 0.25 TeV to 6 TeV. Limits are set also in the context of several scenarios beyond the Standard Model, such as the Sequential Standard Model, a technicolor model, a charged Higgs boson model and a simplified Dark Matter model.

• Determination of jet calibration and energy resolution in proton–proton collisions at $$\sqrt{s} = 8~\hbox {TeV}$$ using the ATLAS detector

  The European Physical Journal C · 2020 · 31 citations

  • Computer Science
  • Physics
  • Nuclear physics

  Abstract The jet energy scale, jet energy resolution, and their systematic uncertainties are measured for jets reconstructed with the ATLAS detector in 2012 using proton–proton data produced at a centre-of-mass energy of 8 TeV with an integrated luminosity of $$20 \, \hbox {fb}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>20</mml:mn> <mml:mspace/> <mml:msup> <mml:mtext>fb</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . Jets are reconstructed from clusters of energy depositions in the ATLAS calorimeters using the anti- $$k_t$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>t</mml:mi> </mml:msub> </mml:math> algorithm. A jet calibration scheme is applied in multiple steps, each addressing specific effects including mitigation of contributions from additional proton–proton collisions, loss of energy in dead material, calorimeter non-compensation, angular biases and other global jet effects. The final calibration step uses several in situ techniques and corrects for residual effects not captured by the initial calibration. These analyses measure both the jet energy scale and resolution by exploiting the transverse momentum balance in $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>γ</mml:mi> </mml:math> + jet, Z + jet, dijet, and multijet events. A statistical combination of these measurements is performed. In the central detector region, the derived calibration has a precision better than 1% for jets with transverse momentum $$150 \, \hbox {GeV} &lt; p_{{\mathrm {T}}}&lt;$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>150</mml:mn> <mml:mspace/> <mml:mtext>GeV</mml:mtext> <mml:mo>&lt;</mml:mo> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> <mml:mo>&lt;</mml:mo> </mml:mrow> </mml:math> 1500 GeV, and the relative energy resolution is $$(8.4\pm 0.6)\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>8.4</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.6</mml:mn> <mml:mo>)</mml:mo> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> for $$p_{{\mathrm {T}}}= 100 \, \hbox {GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>100</mml:mn> <mml:mspace/> <mml:mtext>GeV</mml:mtext> </mml:mrow> </mml:math> and $$(23\pm 2)\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>23</mml:mn> <mml:mo>±</mml:mo> <mml:mn>2</mml:mn> <mml:mo>)</mml:mo> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> for $$p_{{\mathrm {T}}}= 20 \, \hbox {GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>20</mml:mn> <mml:mspace/> <mml:mtext>GeV</mml:mtext> </mml:mrow> </mml:math> . The calibration scheme for jets with radius parameter $$R=1.0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>R</mml:mi> <mml:mo>=</mml:mo> <mml:mn>1.0</mml:mn> </mml:mrow> </mml:math> , for which jets receive a dedicated calibration of the jet mass, is also discussed.

  DOI

Frequent coauthors

• P. H. Hansen

  114 shared

• A. J. Beddall

  Istinye University

  107 shared

• J. Kroll

  University of Pennsylvania

  97 shared

• Z. J. Guo

  96 shared

• T. Carli

  91 shared

• S. A. Olivares Pino

  Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Udine

  91 shared

• M. Shimojima

  87 shared

• S. Oda

  82 shared

Labs

• High Energy Physics Experiment at UMass AmherstPI

Awards & honors

• Outstanding Research Award, UMass Amherst, College of Natura…
• National Science Foundation CAREER Award (2017)
• Ranked Excellent Teacher by Students, University of Illinois…
• ATLAS Thesis Award (2011)