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J. Alcaraz

Publications and source records attributed to J. Alcaraz.

10 recordsLinked to original sources
arXiv2025

The ILD Detector: A Versatile Detector for an Electron-Positron Collider at Energies up to 1 TeV

The International Large Detector, ILD, is a detector concept for an experiment at a future high energy lepton collider. The detector has been optimised for precision physics in a range of energies from 90~GeV to about 1~TeV. ILD features a high precision, large volume combined silicon and gaseous tracking system, together with a high granularity calorimeter, all inside a central solenoidal magnetic field. The paradigm of particle flow has been the guiding principle of the design of ILD. ILD is based mostly on technologies which have been demonstrated by extensive research and test programs. The ILD concept is proposed both for linear and circular lepton collider, be it at CERN or elsewhere. The concept has been developed by a group of nearly 60 institutes from around the world, and offers a well developed and powerful environment for science and technology studies at lepton colliders. In this document, the required performance of the detector, the proposed implementation and the readiness of the different technologies needed for the implementation are discussed.

hep-ex↗
arXiv2019

ProIO: An Event-Based I/O Stream Format for Protobuf Messages

ProIO is a new event-oriented streaming data format which utilizes Google's Protocol Buffers (protobuf) to be flexible and highly language-neutral. The ProIO concept is described here along with its software implementations. The performance of the ProIO concept for a dataset with Monte-Carlo event records used in high-energy physics was benchmarked and compared/contrasted with ROOT I/O. Various combinations of general-purpose compression and variable-length integer encoding available in protobuf were used to investigate the relationship between I/O performance and size-on-disk in a few key scenarios.

physics.comp-ph↗
arXiv2006

An indirect dark matter search with diffuse gamma rays from the Galactic Centre with the Alpha Magnetic Spectrometer

The detection of non-baryonic dark matter through its gamma-ray annihilation in the centre of our galaxy has been studied. The gamma fluxes according to different models have been simulated and compared to those expected to be observed with the Alpha Magnetic Spectrometer (AMS), during a long-term mission on board of the International Space Station. Under the assumption that the dark matter halo is composed of the lightest, stable supersymmetric particle, the neutralino, the results of the simulations in the framework of mSUGRA models, show that with a cuspy dark matter halo or a clumpy halo, the annihilation gamma-ray signal would be detected by AMS. More optimistic perspectives are obtained with the Anomaly Mediated Supersymmetry Breaking (AMSB) model. The latter leads also to a cosmologically important 6Li abundance. Finally, the discovery potential for the massive Kaluza-Klein dark matter candidates has been evaluated and their detection looks feasible.

astro-ph↗
arXiv2006

The Ring Imaging Cherenkov detector (RICH) of the AMS experiment

The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cherenkov (RICH) detector for measuring the electric charge and velocity of the charged cosmic particles. A RICH prototype consisting of 96 photomultiplier units, including a piece of the conical reflector, was built and its performance evaluated with ion beam data. Preliminary results of the in-beam tests performed with ion fragments resulting from collisions of a 158 GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported. The collected data included tests to the final front-end electronics and to different aerogel radiators. Cherenkov rings for a large range of charged nuclei and with reflected photons were observed. The data analysis confirms the design goals. Charge separation up to Fe and velocity resolution of the order of 0.1% for singly charged particles are obtained.

astro-ph↗
arXiv2005

Track fitting in slightly inhomogeneous magnetic fields

A fitting method to reconstruct the momentum and direction of charged particles in slightly inhomogeneous magnetic fields is presented in detail. For magnetic fields of the order of 1 T and inhomogeneity gradients as large as 1 T/m the typical momentum bias due to the proposed approximations is of the order of few MeV, to be compared with scattering components of the order of 20 MeV or even larger. This method is currently being employed in the reconstruction programs of the AMS experiment.

physics.ins-det↗
arXiv2004

The effect of the Galactic gas distribution on the expected cosmic rays spectrum

We will analyze the importance of varying the diffuse gas radial distribution on the resulting expected cosmic rays spectrum. We use the recent HI density data published by Nakanishi et al. (2004), and include them in the cosmic rays propagation code GALPROP (Strong & Moskalenko 1998). We will obtain those models that reproduce the characteristics shown by the cosmic rays data, and we will then extract information about the Galaxy structure.

astro-ph↗
arXiv2003

Limits on the brane fluctuations mass and on the brane tension scale from electron-positron colliders

In the context of the brane-world scenarios with compactified large extra dimensions, we study the production of the possible massive brane oscillations (branons) in electron-positron colliders. We compute their contribution to the electroweak gauge bosons decay width and to the single-photon and single-Z processes. With LEP-I results and assuming non observation at LEP-II, we present exclusion plots for the brane tension $τ= f^4$ and the branon mass $M$. Prospects for the next generation of electron-positron colliders are also considered.

hep-ph↗
arXiv2002

On the Experimental Effects of the Off-shell Structure in Anomalous Neutral Triple Gauge Vertices

We discuss differences between on-shell and off-shell treatments in the search for anomalous neutral triple gauge couplings in $\mathrm{e^+ e^-}$ collisions. We find that the usual on-shell framework represents an optimal starting point, covering all scenarios in which a reasonable experimental sensitivity is expected. We show that off-shell effects lead to negligible deviations at the experimental level, provided that $\mathrm{e^+ e^-}\to\mathrm{f}\bar{\mathrm{f}}γ$ and $\mathrm{e^+ e^-}\to\mathr performed in regions where $\mathrm{Z}^*\to\mathrm{f}\bar{\mathrm{f}},\mathrm{f^\prime}\math production is dominant. For consistency reasons, we advocate the use of a natural extension of the on-shell definitions, which takes into account the correct off-shell dependences. Contrary to what has been recently suggested in the literature, we find that no $SU(2)_L\times U(1)_Y$ constraints among neutral triple gauge couplings can be imposed in a general case.

hep-ph↗
arXiv2000

Anomalous Gauge Boson Couplings in the e^+ e^- -> ZZ Process

We discuss experimental aspects related to the $\mathrm{e^+ e^-} \to \mathrm{Z}\mathrm{Z}$ process and to the search for anomalous ZZV couplings (V$= \mathrm{Z}, γ$) at LEP2 and future $\mathrm{e^+ e^-}$ colliders. We present two possible approaches for a realistic study of the reaction and discuss the differences between them. We find that the optimal method to study double Z resonant production and to quantify the presence of anomalous couplings requires the use of a complete four-fermion final-state calculation.

hep-ph↗