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Simulations and Performance Studies for the Forward Liquid Argon Experiment (FLArE) at the Forward Physics Facility
No full textFLArE (Forward Liquid Argon Experiment) is a proposed Liquid Argon Time Projection Chamber (LArTPC) detector designed for very high-energy neutrinos and dark matter searches in the Forward Physics Facility (FPF), about in the far-forward direction from the ATLAS interaction point at the Large Hadron Collider (LHC). This technical note describes the details of the simulation efforts performed for the design and optimization of the detector. The document summarizes the status of the current studies including possible improvements and future items to investigate. This note is complemented by a separate note on the technical design and integration in the facility
Searches for Dark Matter and other exotic particles from ATLAS and CMS
No full textMany theories beyond the Standard Model (SM) have been proposed to address several of the SM shortcomings: explaining the presence of a non-baryonic Dark Matter (DM) component in the Universe, why the Higgs boson is so light, the origin of neutrino masses, or the observed pattern of masses and mixing angles in the quark and lepton sectors. Many of these beyond-the-SM extensions predict new particles or interactions directly accessible at the LHC, including various DM candidates and supersymmetrical particles. This talk will present recent searches by the ATLAS detector at the LHC, their interplay, and interpretation
Tuning the CMS Coffea-casa facility for 200 Gbps Challenge
No full textAs a part of the IRIS-HEP "Analysis Grand Challenge" activities, the Coffea-casa AF team executed a "200 Gbps Challenge". One of the goals of this challenge was to provide a setup for execution of a test notebook-style analysis on the facility that could process a 200 TB CMS NanoAOD dataset in 20 minutes. We describe the solutions we deployed at the facility to execute the challenge tasks. The facility was configured to provide 2000+ cores for quick turn-around, low-latency analysis. To reach the highest event processing rates we tested different scaling backends, both scaling over HTCondor and Kubernetes resources and using Dask and Taskvine schedulers. This configuration also allowed us to compare two different services for managing Dask clusters, Dask labextention, and Dask Gateway server, under extreme conditions. A robust set of XCache servers with a redirector were deployed in Kubernetes to cache the dataset to minimize wide-area network traffic. The XCache servers were backed with solid-state NVME drives deployed within the Kubernetes cluster nodes. All data access was authenticated using scitokens and was transparent to the user. To ensure we could track and measure data throughput precisely, we used our existing Prometheus monitoring stack to monitor the XCache pod throughput on the Kubernetes network layer. Using the rate query across all of the 8 XCache pods we were able to view a stacked cumulative graph of the total throughput for each XCache. This monitoring setup allowed us to ensure uniform data rates across all nodes while verifying we had reached the 200 Gbps benchmark
Review of VBS EFT MC modelling in ATLAS and CMS
No full textJoint ATLAS-CMS presentation at the COMETA EFT Workshop in Paris, March 17-1
Heavy-ion physics highlights from ATLAS
No full textRecent measurements from the heavy-ion physics programme from the ATLAS experiment at the LHC are reviewed. They include azimuthal flow at high transverse momenta (), fluctuations in lead-lead and xenon-xenon collisions, jet-radius dependence of di-jet asymmetry, and an observation of top-quark pair production in proton-lead and lead-lead systems. Results of a search for a diffusion wake in -jet events are also discussed. Moreover, results from ultra-peripheral collisions for photonuclear di-jet production and a search for magnetic monopoles are presented
Finite-temperature bubble nucleation with shifting scale hierarchies
No full textFocusing on supercooled phase transitions in models with classical scale symmetry, we formulate a state-of-the art framework for computing the bubble nucleation rate, accounting for the presence of varying energy scales. In particular, we examine the limitations of derivative expansions in constructing a thermal effective field theory for bubble nucleation. We show that for gauge-field fluctuations, derivative expansions diverge after the two leading orders due to the strong variation in gauge-field masses between the high- and low-temperature phases. By directly computing these contributions using the fluctuation determinant, we capture these effects while also accounting for the dominant contribution at two-loop. Finally, we demonstrate how this approach significantly improves nucleation rate calculations compared to leading-order results, providing a more robust framework for predicting gravitational-wave signals from supercooled phase transitions in models such as the SU(2)cSM.Focusing on supercooled phase transitions in models with classical scale symmetry, we formulate a state-of-the art framework for computing the bubble-nucleation rate, accounting for the presence of various energy scales. In particular, we examine the limitations of derivative expansions in constructing a thermal effective field theory for bubble nucleation. We show that for gauge field fluctuations, derivative expansions diverge after the leading two orders due to the strong variation in gauge field masses between the high- and low-temperature phases. By directly computing these contributions using the fluctuation determinant, we capture these effects while also accounting for large explicit logarithms at two loops, utilising the exact renormalisation group structure of the EFT. Finally, we demonstrate how this approach significantly improves nucleation rate calculations compared to leading-order results, providing a more robust framework for predicting gravitational-wave signals from supercooled phase transitions in models such as the SU(2)cSM
Characterization of Markarian 421 during its most violent year: Multiwavelength variability and correlations
No full textAims. Mrk 421 was in its most active state around early 2010, which led to the highest TeV gamma-ray flux ever recorded from any active galactic nuclei (AGN). We aim to characterize the multiwavelength behavior during this exceptional year for Mrk 421, and evaluate whether it is consistent with the picture derived with data from other less exceptional years.Methods. We investigated the period from November 5, 2009, (MJD 55140) until July 3, 2010, (MJD 55380) with extensive coverage from very-high-energy (VHE; E > 100 GeV) gamma rays to radio with MAGIC, VERITAS, Fermi-LAT, RXTE, Swift, GASP-WEBT, VLBA, and a variety of additional optical and radio telescopes. We characterized the variability by deriving fractional variabilities as well as power spectral densities (PSDs). In addition, we investigated images of the jet taken with VLBA and the correlation behavior among different energy bands.Results. Mrk 421 was in widely different states of activity throughout the campaign, ranging from a low-emission state to its highest VHE flux ever recorded. We find the strongest variability in X-rays and VHE gamma rays, and PSDs compatible with power-law functions with indices around 1.5. We observe strong correlations between X-rays and VHE gamma rays at zero time lag with varying characteristics depending on the exact energy band. We also report a marginally significant (∼3σ) positive correlation between high-energy (HE; E > 100 MeV) gamma rays and the ultraviolet band. We detected marginally significant (∼3σ) correlations between the HE and VHE gamma rays, and between HE gamma rays and the X-ray, that disappear when the large flare in February 2010 is excluded from the correlation study, hence indicating the exceptionality of this flaring event in comparison with the rest of the campaign. The 2010 violent activity of Mrk 421 also yielded the first ejection of features in the VLBA images of the jet of Mrk 421. Yet the large uncertainties in the ejection times of these unprecedented radio features prevent us from firmly associating them to the specific flares recorded during the 2010 campaign. We also show that the collected multi-instrument data are consistent with a scenario where the emission is dominated by two regions, a compact and extended zone, which could be considered as a simplified implementation of an energy-stratified jet as suggested by recent IXPE observations.Key words: galaxies: active / BL Lacertae objects: individual: Mrk 421Mrk 421 was in its most active state around early 2010, which led to the highest TeV gamma-ray flux ever recorded from any active galactic nuclei. We aim to characterize the multiwavelength behavior during this exceptional year for Mrk 421, and evaluate whether it is consistent with the picture derived with data from other less exceptional years. We investigated the period from November 5, 2009, (MJD 55140) until July 3, 2010, (MJD 55380) with extensive coverage from very-high-energy (VHE; E100GeV) gamma rays to radio with MAGIC, VERITAS, Fermi-LAT, RXTE, Swift, GASP-WEBT, VLBA, and a variety of additional optical and radio telescopes. We investigated the variability and correlation behavior among different energy bands in great detail. We find the strongest variability in X-rays and VHE gamma rays, and PSDs compatible with power-law functions. We observe strong correlations between X-rays and VHE gamma rays. We also report a marginally significant positive correlation between high-energy (HE; E100MeV) gamma rays and the ultraviolet band. We detected marginally significant correlations between the HE and VHE gamma rays, and between HE gamma rays and the X-ray, that disappear when the large flare in February 2010 is excluded from the correlation study. The activity of Mrk 421 also yielded the first ejection of features in the VLBA images of the jet of Mrk 421. Yet the large uncertainties in the ejection times of these radio features prevent us from firmly associating them to the specific flares recorded during the campaign. We also show that the collected multi-instrument data are consistent with a scenario where the emission is dominated by two regions, a compact and extended zone, which could be considered as a simplified implementation of an energy-stratified jet as suggested by recent IXPE observations
Measurement of production cross-section at 13.6 TeV with the CMS experiment
No full textThe first measurements of production cross section in proton-proton collisions at a centre-of-mass energy of 13.6 TeV are presented.
The data used were recorded with the CMS detector at the LHC in 2022, corresponding to an integrated luminosity of 34.8 fb.
The events are selected by requiring one electron and one muon of opposite charge.
The total inclusive cross section is measured to be ~pb, consistent with the standard model predictions.
Fiducial cross sections are also reported as a function of the jet multiplicity in the event and compared with different theoretical predictions
Projections for top quark mass measurements at the HL-LHC
No full textIn the context of the Update on the European Strategy in Particle Physics, we present the current expectation for the achievable precision in top quark mass measurements at the HL-LHC. The projections are based on two methods that are expected to profit significantly from the large amount of data expected at the HL-LHC
HL-LHC projections for searches for new resonances
No full textSensitivity estimates to search for new spin-0 resonances at HL-LHC are presented in the decay channels to two Z bosons or two top quarks. Using searches conducted with Run 2 data collected by the CMS detector from 2016 to 2018 at a center-of-mass energy of 13 TeV, results are projected to integrated luminosities of 4 and 6 , at a center-of-mass energy of 14 TeV, corresponding to the sum of data collected by ATLAS and CMS detectors. Expected exclusion limits at 95\% confidence level on cross sections or coupling strengths are computed as a function of the resonance mass for both decay channels, under different assumptions on decay width and production mechanisms