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Recent results on heavy H/A bosons at CMS
No full textThe study of additional Higgs bosons at the LHC provides a unique opportunity to probe Higgs boson couplings and search for signs of physics beyond the Standard Model. In these proceedings, recent results on new scalar boson searches with the CMS experiment, in various decay channels and production modes, are presented
Search for microscopic black holes and sphalerons in proton-proton collisions at 13 TeV
No full textA search for microscopic black holes and sphalerons using proton-proton collisions at recorded by the CMS detector during the data taking, and corresponding to an integrated luminosity of , is presented. Two data-driven search strategies are used. Model independent limits on the cross section of a new physics signal with multiple jets and leptons are set using a method that relies on the shape invariance of the scalar sum of the transverse momenta of all objects in the event. Model dependent limits on black hole and sphaleron production are set using a newly introduced method that has been developed for the identification of collider events with distinct kinematic features by separating them into classes based on phase-space proximity.
In the context of models with large extra dimensions, semiclassical black holes with masses below
are excluded, significantly extending the reach in comparison to limits from previous searches. At confidence limit, more than 3 extra dimensions are excluded for most models probed. Results of a dedicated search for electroweak sphalerons are used to derive an upper limit of 0.0025 at confidence level on the fraction of all quark-quark interactions above the nominal threshold of energy for the sphaleron transition
Experimental evaluation of a thermal interface and a cold circulator used in remote cooling loop driven by a cryocooler
No full textDue to helium’s limited accessibility and non-renewable nature, superconducting systems need more sustainable alternatives to cryogenic plants, which feature elevated helium losses. Cryogenic systems based on commercially available cryocoolers are seen as a promising solution. In this paper, a remote cooling loop driven by a cryocooler and cold circulator is introduced, and an experimental study of the heat exchanger serving as the cryocooler-to-gas thermal interface is presented. This thermal interface is intended for integration into a remote cooling system, which is designed to intercept the 300 W heat load from 3 kA hybrid current leads. The heat exchanger successfully maintained a gas outlet temperature below 50 K under 300 W. A mathematical model is developed to forecast both the gas outlet temperatures and the cooling capacity of the heat exchanger for a given geometry, and validation is conducted using experimental data. Furthermore, an experimental verification of the isentropic efficiency of the selected cold circulator is included. Finally, an estimation of the mass flow within the hydraulic system is presented and compared with the measured results. •The study explores cryocoolers as compact, low-maintenance alternatives to cryogenic plants for cooling superconducting magnets.•A remote cooling loop using a single-stage cryocooler and cold circulator is investigated.•A simplified mathematical model for thermal calculations of the cryocooler-to-cryogen thermal interface heat exchanger is developed.•Experimental results for the cryocooler-to-cryogen thermal interface and cold circulator performance are presented
Exhibition FCC
No full textThis collection features 11 visually engaging posters tracing CERN’s evolution — from its pioneering discoveries and groundbreaking technologies to the vision of the Future Circular Collider (FCC), an international endeavour designed to extend our quest for knowledge into the post-LHC era. Together, these posters highlight CERN’s enduring role at the forefront of global scientific exploration
WLCG transition from X.509 to Tokens: Progress and Outlook
No full textSince 2017, the Worldwide LHC Computing Grid (WLCG) has been working towards enabling token-based authentication and authorization throughout its entire middleware stack.Taking guidance from the WLCG Token Transition Timeline, published in 2022, substantial progress has been achieved not only in making middleware compatible with the use of tokens, but also in understanding the limitations of the WLCG Common JWT Profiles, first published in 2019. Significant scalability experience has been gained from Data Challenge 2024, during which millions of files were transferred with tokens used as credentials - a significant percentage of the total transfers completed.Besides describing the state of affairs in the transition to tokens, revisions to the WLCG token profile, and the evolving road maps, this contribution also covers the corresponding transition from VOMS-Admin to INDIGO-IAM services, with continuing improvements in terms of functionality as well as deployment
LbMCSubmit: Streamlined production and submission of LHCb MC requests
No full textThe LHCb experiment requires a wide variety of Monte Carlo simulated samples to support its physics programme and detector upgrade studies. Millions of events are typically requested, so the production system is run centrally via DIRAC on LHCb’s distributed computing resources to handle the demand. To streamline this process, well-defined configurations for request generation and a robust platform for submission, review, and discussion are essential. The package LbMCSubmit was introduced to simplify request definition using a rule-based approach, resolving combinatorial complexities and allowing users to generate full configurations from a structured set of inputs. For submission, a GitLab-based workflow was developed, integrating request submission, review, and automated testing via Continuous Integration (CI). Requests are submitted through GitLab’s merge request system, where they undergo validation before being sent to DIRAC. Introduced in spring 2023 and continuously updated, this system has become the standard for LHCb simulation requests
Versioning of the DD4hep-based LHCb Detector Description
No full textThe LHCb Detector software project is home to the detector description of the LHCb experiment, utilized across all data processing applications, from simulation to reconstruction. It is based on the DD4hep package relying on the combination of XML files and C++ code. A suite of custom developments were introduced to support different versions of the detector layout in different data taking periods.The detector descriptions are organized into self-contained, versioned component folders, each containing C++ code and DD4hep CompactXML files. The description of the overall LHCb detector combines specific versions of the components for the period being described. When a sub-detector is identical in two LHCb layouts it can be loaded by both, avoiding code duplication and facilitating future upgrade simulation studies. A convention for naming the versions consistent between the components and the whole detector has been set up. Dependency and convention checks as well as geometry monitoring are enforced by using GitLab’s CI testing. Critically, they include verifications that changes introduced do not affect existing versions