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M. G. Albrow

Publications and source records attributed to M. G. Albrow.

17 recordsLinked to original sources
arXiv2025

PREFACE: A search for long-lived particles at the Large Hadron Collider

The Standard Model (SM) fails to explain many problems (neutrino masses, dark matter, and matter-antimatter asymmetry, among others) that may be resolved with new particles beyond the Standard model (BSM). The fact that such new particles are not yet observed may be explained either by their too high mass or by very small coupling to SM particles. The latter case implies long lifetimes. Such long-lived particles (LLPs) would have signatures different from those of SM particles. Searches in the "central region" are covered by the LHC general purpose experiments. The forward small angle region far from the interaction point (IP) is unexplored. Such particles would have large energy $E$ = $\mathcal{O}$(1~TeV) and Lorentz time dilation factor $γ= E/m \approx 10^2 - 10^{3}$, hence long decay distances. A new class of specialized LHC detectors dedicated to LLP searches has been proposed for the forward regions. Among these experiments, FASER is already operational, and FACET is under consideration at a location 100 meters from IP5 (the CMS intersection). However, some features of FACET require a specially enlarged beam pipe, which cannot be implemented for Run 4. In this study, we explore a simplified version of the proposed detector, PREFACE, compatible with the standard LHC beam pipe in the HL-LHC in Run 4. Realistic Geant4 simulations are performed and the background is evaluated. A preliminary analysis of the physics potential with the PREFACE geometry indicates that several significant channels could be accessible with sensitivities comparable to FACET and other LLP searches.

hep-ex↗
arXiv2023

Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers

The present white paper is submitted as part of the "Snowmass" process to help inform the long-term plans of the United States Department of Energy and the National Science Foundation for high-energy physics. It summarizes the science questions driving the Ultra-High-Energy Cosmic-Ray (UHECR) community and provides recommendations on the strategy to answer them in the next two decades.

astro-ph.HE↗
arXiv2022

FACET: A new long-lived particle detector in the very forward region of the CMS experiment

We describe a proposal to add a set of very forward detectors to the CMS experiment for the high-luminosity era of the Large Hadron Collider to search for beyond the standard model long-lived particles, such as dark photons, heavy neutral leptons, axion-like particles, and dark Higgs bosons. The proposed subsystem is called FACET for Forward-Aperture CMS ExTension, and will be sensitive to any particles that can penetrate at least 50 m of magnetized iron and decay in an 18 m long, 1 m diameter vacuum pipe. The decay products will be measured in detectors using identical technology to the planned CMS Phase-2 upgrade.

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↗
arXiv2012

Quartz Cherenkov Counters for Fast Timing: QUARTIC

We have developed particle detectors based on fused silica (quartz) Cherenkov radiators read out with micro-channel plate photomultipliers (MCP-PMTs) or silicon photomultipliers (SiPMs) for high precision timing (Sigma(t) about 10-15 ps). One application is to measure the times of small angle protons from exclusive reactions, e.g. p + p - p + H + p, at the Large Hadron Collider, LHC. They may also be used to measure directional particle fluxes close to external or stored beams. The detectors have small areas (square cm), but need to be active very close (a few mm) to the intense LHC beam, and so must be radiation hard and nearly edgeless. We present results of tests of detectors with quartz bars inclined at the Cherenkov angle, and with bars in the form of an "L" (with a 90 degree corner). We also describe a possible design for a fast timing hodoscope with elements of a few square mm.

physics.ins-det↗
arXiv2012

Observation of Exclusive Gamma Gamma Production in p pbar Collisions at sqrt{s}=1.96 TeV

We have observed exclusive γγproduction in proton-antiproton collisions at \sqrt{s}=1.96 TeV, using data from 1.11 \pm 0.07 fb^{-1} integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E_T > 2.5 GeV and pseudorapidity |η| < 1.0, with no other particles detected in -7.4 < η< +7.4. The two showers have similar E_T and azimuthal angle separation Δϕ\sim π; 34 events have two charged particle tracks, consistent with the QED process p \bar{p} to p + e^+e^- + \bar{p} by two-photon exchange, while 43 events have no charged tracks. The number of these events that are exclusive π^0π^0 is consistent with zero and is < 15 at 95% C.L. The cross section for p\bar{p} to p+γγ+\bar{p} with |η(γ)| < 1.0 and E_T(γ) > 2.5$ GeV is 2.48^{+0.40}_{-0.35}(stat)^{+0.40}_{-0.51}(syst) pb.

hep-ex↗
arXiv2010

Accelerator Data for Cosmic Ray Physics

I present selected examples of accelerator data, mainly from hadron colliders, that are relevant for understanding cosmic ray showers. I focus on the forward region, $x_{Feynman} > 0.05$, where high energy data are scarce, since the emphasis in collider physics became high-$p_T$ phenomena.

hep-ex↗
arXiv2010

Central Exclusive Particle Production at High Energy Hadron Colliders

We review the subject of central exclusive particle production at high energy hadron colliders. In particular we consider reactions of the type A + B -> A + X + B, where X is a fully specified system of particles that is well separated in rapidity from the outgoing beam particles. We focus on the case where the colliding particles are strongly interacting and mainly they will be protons (or antiprotons) as at the ISR, SppS, Tevatron and LHC. The data are surveyed and placed within the context of theoretical developments.

hep-ph↗
arXiv2009

The FP420 R&D Project: Higgs and New Physics with forward protons at the LHC

We present the FP420 R&D project, which has been studying the key aspects of the development and installation of a silicon tracker and fast-timing detectors in the LHC tunnel at 420 m from the interaction points of the ATLAS and CMS experiments. These detectors would measure precisely very forward protons in conjunction with the corresponding central detectors as a means to study Standard Model (SM) physics, and to search for and characterise New Physics signals. This report includes a detailed description of the physics case for the detector and, in particular, for the measurement of Central Exclusive Production, pp --> p + phi + p, in which the outgoing protons remain intact and the central system phi may be a single particle such as a SM or MSSM Higgs boson. Other physics topics discussed are gamma-gamma and gamma-p interactions, and diffractive processes. The report includes a detailed study of the trigger strategy, acceptance, reconstruction efficiencies, and expected yields for a particular p p --> p H p measurement with Higgs boson decay in the b-bbar mode. The document also describes the detector acceptance as given by the LHC beam optics between the interaction points and the FP420 location, the machine backgrounds, the new proposed connection cryostat and the moving ("Hamburg") beam-pipe at 420 m, and the radio-frequency impact of the design on the LHC. The last part of the document is devoted to a description of the 3D silicon sensors and associated tracking performances, the design of two fast-timing detectors capable of accurate vertex reconstruction for background rejection at high-luminosities, and the detector alignment and calibration strategy.

hep-ex↗
arXiv2005

A Search for the Higgs Boson using Very Forward Tracking Detectors with CDF

We propose to add high precision track detectors 55m downstream on both (E&W) sides of CDF, to measure high Feynman-x protons and antiprotons in association with central states. A primary motivation is to search for the Higgs boson, and if it is seen to measure its mass precisely. The track detectors will be silicon strip telescopes backed up by high resolution time-of-flight counters. The addition of these small detectors effectively converts the Tevatron into a gluon-gluon collider with sqrt{s} from 0 to ~ 200 GeV. This experiment will also measure millions/year clean high-|t| elastic scattering events and produce millions of pure gluon jets. Besides a wealth of unique QCD studies we will search for signs of exotic physics such as SUSY and Large Extra Dimensions.

hep-ex↗
arXiv2005

Search for First-Generation Scalar Leptoquarks in $\bm{p \bar{p}}$ collisions at $\sqrt{s}$=1.96 TeV

We report on a search for pair production of first-generation scalar leptoquarks ($LQ$) in $p \bar{p}$ collisions at $\sqrt{s}$=1.96 TeV using an integrated luminosity of 203 $pb^{-1}$ collected at the Fermilab Tevatron collider by the CDF experiment. We observe no evidence for $LQ$ production in the topologies arising from $LQ \bar{LQ} \to eqeq$ and $LQ \bar{LQ} \to eq νq$, and derive 95% C.L. upper limits on the $LQ$ production cross section. %as a function of $β$, where $β$ is the branching fraction for $LQ \to eq$. The results are combined with those obtained from a separately reported CDF search in the topology arising from $LQ\bar{LQ} \to νq νq$ and 95% C.L. lower limits on the LQ mass as a function of $β= BR(LQ \to eq) $ are derived. The limits are 236, 205 and 145 GeV/c$^2$ for $β$ = 1, $β$ = 0.5 and $β$ = 0.1, respectively.

hep-ex↗
arXiv2004

Comparison of Three-jet Events in Proton-Antiproton Collisions at Center-of-mass Energy 1.8 TeV to Predictions from a Next-to-leading Order QCD Calculation

The properties of three-jet events with total transverse energy greater than 320 GeV and individual jet energy greater than 20 GeV have been analyzed and compared to absolute predictions from a next-to-leading order (NLO) perturbative QCD calculation. These data, of integrated luminosity 86 pb^-1, were recorded by the CDF Experiment for proton-antiproton collisions at sqrt{s}=1.8 TeV. This study tests a model of higher order QCD processes that result in gluon emission and can be used to estimate the magnitude of the contribution of processes higher than NLO. The total cross section is measured to be 466 +/- 3(stat.)^{+207}_{-70}(syst.) pb. The differential cross section is furthermore measured for all kinematically accessible regions of the Dalitz plane, including those for which the theoretical prediction is unreliable. While the measured cross section is consistent with the theoretical prediction in magnitude, the two differ somewhat in shape in the Dalitz plane.

hep-ex↗
arXiv2003

Observation of the Narrow State $X(3872)\to J/ψπ^{+}π^{-}$ in $\bar{p}p$ Collisions at $\sqrt{s}=1.96 \TeV$

We report the observation of a narrow state decaying into $J/ψπ^+π^-$ and produced in $220 pb^{-1}$ of $\bar{p} p $ collisions at $\sqrt{s}=1.96 TeV$ in the CDF II experiment. We observe $ 730 \pm 90 $ decays. The mass is measured to be $3871.3 \pm 0.7 (stat) \pm 0.4 (syst) MeV/c2$, with an observed width consistent with the detector resolution. This is in agreement with the recent observation by the Belle Collaboration of the X(3872) meson.

hep-ex↗
arXiv2000

Searching for the Higgs Boson at Hadron Colliders using the Missing Mass Method

If the Higgs is produced with a large enough cross section in the {\em exclusive} reaction $p + \bar{p} \to p + H + \bar{p}$ it will give rise to a peak at $M_H$ in the {\em missing mass} ($MM$) spectrum, calculated from the 4-momenta of the beam particles and the outgoing $p$ and $\bar{p}$. The resolution in $MM$ can be approximately 250 MeV, independent of $M_H$ from 100 GeV to 200 GeV. This high resolution makes a search feasible over nearly this full mass range at the Tevatron with 15 fb$^{-1}$ as hoped for in Run II.

hep-ph↗