23 research outputs found
FASER: ForwArd Search ExpeRiment at the LHC
FASER, the ForwArd Search ExpeRiment, is a proposed experiment dedicated to
searching for light, extremely weakly-interacting particles at the LHC. Such
particles may be produced in the LHC's high-energy collisions in large numbers
in the far-forward region and then travel long distances through concrete and
rock without interacting. They may then decay to visible particles in FASER,
which is placed 480 m downstream of the ATLAS interaction point. In this work,
we describe the FASER program. In its first stage, FASER is an extremely
compact and inexpensive detector, sensitive to decays in a cylindrical region
of radius R = 10 cm and length L = 1.5 m. FASER is planned to be constructed
and installed in Long Shutdown 2 and will collect data during Run 3 of the 14
TeV LHC from 2021-23. If FASER is successful, FASER 2, a much larger successor
with roughly R ~ 1 m and L ~ 5 m, could be constructed in Long Shutdown 3 and
collect data during the HL-LHC era from 2026-35. FASER and FASER 2 have the
potential to discover dark photons, dark Higgs bosons, heavy neutral leptons,
axion-like particles, and many other long-lived particles, as well as provide
new information about neutrinos, with potentially far-ranging implications for
particle physics and cosmology. We describe the current status, anticipated
challenges, and discovery prospects of the FASER program.Comment: 13 pages, 4 figures, submitted as Input to the European Particle
Physics Strategy Update 2018-2020 and draws on FASER's Letter of Intent,
Technical Proposal, and physics case documents (arXiv:1811.10243,
arXiv:1812.09139, and arXiv:1811.12522
Letter of Intent for FASER: ForwArd Search ExpeRiment at the LHC
FASER is a proposed small and inexpensive experiment designed to search for
light, weakly-interacting particles at the LHC. Such particles are dominantly
produced along the beam collision axis and may be long-lived, traveling
hundreds of meters before decaying. To exploit both of these properties, FASER
is to be located along the beam collision axis, 480 m downstream from the ATLAS
interaction point, in the unused service tunnel TI18. We propose that FASER be
installed in TI18 in Long Shutdown 2 in time to collect data from 2021-23
during Run 3 of the 14 TeV LHC. FASER will detect new particles that decay
within a cylindrical volume with radius R= 10 cm and length L = 1.5 m. With
these small dimensions, FASER will complement the LHC's existing physics
program, extending its discovery potential to a host of new particles,
including dark photons, axion-like particles, and other CP-odd scalars. A FLUKA
simulation and analytical estimates have confirmed that numerous potential
backgrounds are highly suppressed at the FASER location, and the first in situ
measurements are currently underway. We describe FASER's location and discovery
potential, its target signals and backgrounds, the detector's layout and
components, and the experiment's preliminary cost estimate, funding, and
timeline.Comment: 23 pages, 13 figures; submitted to the CERN LHCC on 18 July 201
Technical Proposal for FASER: ForwArd Search ExpeRiment at the LHC
FASER is a proposed small and inexpensive experiment designed to search for
light, weakly-interacting particles during Run 3 of the LHC from 2021-23. Such
particles may be produced in large numbers along the beam collision axis,
travel for hundreds of meters without interacting, and then decay to standard
model particles. To search for such events, FASER will be located 480 m
downstream of the ATLAS IP in the unused service tunnel TI12 and be sensitive
to particles that decay in a cylindrical volume with radius R=10 cm and length
L=1.5 m. FASER will complement the LHC's existing physics program, extending
its discovery potential to a host of new, light particles, with potentially
far-reaching implications for particle physics and cosmology.
This document describes the technical details of the FASER detector
components: the magnets, the tracker, the scintillator system, and the
calorimeter, as well as the trigger and readout system. The preparatory work
that is needed to install and operate the detector, including civil
engineering, transport, and integration with various services is also
presented. The information presented includes preliminary cost estimates for
the detector components and the infrastructure work, as well as a timeline for
the design, construction, and installation of the experiment.Comment: 82 pages, 62 figures; submitted to the CERN LHCC on 7 November 201
FASER's Physics Reach for Long-Lived Particles
FASER,the ForwArd Search ExpeRiment,is a proposed experiment dedicated to
searching for light, extremely weakly-interacting particles at the LHC. Such
particles may be produced in the LHC's high-energy collisions and travel long
distances through concrete and rock without interacting. They may then decay to
visible particles in FASER, which is placed 480 m downstream of the ATLAS
interaction point. In this work we briefly describe the FASER detector layout
and the status of potential backgrounds. We then present the sensitivity reach
for FASER for a large number of long-lived particle models, updating previous
results to a uniform set of detector assumptions, and analyzing new models. In
particular, we consider all of the renormalizable portal interactions, leading
to dark photons, dark Higgs bosons, and heavy neutral leptons (HNLs); light B-L
and gauge bosons; axion-like particles (ALPs) that are coupled
dominantly to photons, fermions, and gluons through non-renormalizable
operators; and pseudoscalars with Yukawa-like couplings. We find that FASER and
its follow-up, FASER 2, have a full physics program, with discovery sensitivity
in all of these models and potentially far-reaching implications for particle
physics and cosmology
First Direct Observation of Collider Neutrinos with FASER at the LHC
We report the first direct observation of neutrino interactions at a particle
collider experiment. Neutrino candidate events are identified in a 13.6 TeV
center-of-mass energy collision data set of 35.4 fb using the
active electronic components of the FASER detector at the Large Hadron
Collider. The candidates are required to have a track propagating through the
entire length of the FASER detector and be consistent with a muon neutrino
charged-current interaction. We infer neutrino interactions
with a significance of 16 standard deviations above the background-only
hypothesis. These events are consistent with the characteristics expected from
neutrino interactions in terms of secondary particle production and spatial
distribution, and they imply the observation of both neutrinos and
anti-neutrinos with an incident neutrino energy of significantly above 200 GeV.Comment: Submitted to PRL on March 24 202
First neutrino interaction candidates at the LHC
FASER at the CERN Large Hadron Collider (LHC) is designed to directly
detect collider neutrinos for the first time and study their cross sections at
TeV energies, where no such measurements currently exist. In 2018, a pilot
detector employing emulsion films was installed in the far-forward region of
ATLAS, 480 m from the interaction point, and collected 12.2 fb of
proton-proton collision data at a center-of-mass energy of 13 TeV. We describe
the analysis of this pilot run data and the observation of the first neutrino
interaction candidates at the LHC. This milestone paves the way for high-energy
neutrino measurements at current and future colliders.Comment: Auxiliary materials are available at
https://faser.web.cern.ch/fasernu-first-neutrino-interaction-candidate
The FASER Detector
FASER, the ForwArd Search ExpeRiment, is an experiment dedicated to searching
for light, extremely weakly-interacting particles at CERN's Large Hadron
Collider (LHC). Such particles may be produced in the very forward direction of
the LHC's high-energy collisions and then decay to visible particles inside the
FASER detector, which is placed 480 m downstream of the ATLAS interaction
point, aligned with the beam collisions axis. FASER also includes a
sub-detector, FASER, designed to detect neutrinos produced in the LHC
collisions and to study their properties. In this paper, each component of the
FASER detector is described in detail, as well as the installation of the
experiment system and its commissioning using cosmic-rays collected in
September 2021 and during the LHC pilot beam test carried out in October 2021.
FASER will start taking LHC collision data in 2022, and will run throughout LHC
Run 3
FASER's physics reach for long-lived particles
The ForwArd Search ExpeRiment (FASER) is an approved experiment dedicated to searching for light, extremely weakly interacting particles at the LHC. Such particles may be produced in the LHC's high-energy collisions and travel long distances through concrete and rock without interacting. They may then decay to visible particles in FASER, which is placed 480 m downstream of the ATLAS interaction point. In this work we briefly describe the FASER detector layout and the status of potential backgrounds. We then present the sensitivity reach for FASER for a large number of long-lived particle models, updating previous results to a uniform set of detector assumptions, and analyzing new models. In particular, we consider all of the renormalizable portal interactions, leading to dark photons, dark Higgs bosons, and heavy neutral leptons; light BâL and LiâLj gauge bosons; axionlike particles that are coupled dominantly to photons, fermions, and gluons through nonrenormalizable operators; and pseudoscalars with Yukawa-like couplings. We find that FASER and its follow-up, FASER 2, have a full physics program, with discovery sensitivity in all of these models and potentially far-reaching implications for particle physics and cosmology
Detecting and studying high-energy collider neutrinos with FASER at the LHC
Neutrinos are copiously produced at particle colliders, but no collider neutrino has ever been detected. Colliders produce both neutrinos and anti-neutrinos of all flavors at very high energies, and they are therefore highly complementary to those from other sources. FASER, the Forward Search Experiment at the LHC, is ideally located to provide the first detection and study of collider neutrinos. We investigate the prospects for neutrino studies with FASER Îœ, a proposed component of FASER, consisting of emulsion films interleaved with tungsten plates with a total target mass of 1.2 t, to be placed on-axis at the front of FASER. We estimate the neutrino fluxes and interaction rates, describe the FASER Îœ detector, and analyze the characteristics of the signals and primary backgrounds. For an integrated luminosity of 150fb-1 to be collected during Run 3 of the 14 TeV LHC in 2021â23, approximately 1300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASER Îœ, with mean energies of 600 GeV to 1 TeV. With such rates and energies, FASER will measure neutrino cross sections at energies where they are currently unconstrained, will bound models of forward particle production, and could open a new window on physics beyond the standard model
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Letter of Intent for FASER: ForwArd Search ExpeRiment at the LHC
FASER is a proposed small and inexpensive experiment designed to search for
light, weakly-interacting particles at the LHC. Such particles are dominantly
produced along the beam collision axis and may be long-lived, traveling
hundreds of meters before decaying. To exploit both of these properties, FASER
is to be located along the beam collision axis, 480 m downstream from the ATLAS
interaction point, in the unused service tunnel TI18. We propose that FASER be
installed in TI18 in Long Shutdown 2 in time to collect data from 2021-23
during Run 3 of the 14 TeV LHC. FASER will detect new particles that decay
within a cylindrical volume with radius R= 10 cm and length L = 1.5 m. With
these small dimensions, FASER will complement the LHC's existing physics
program, extending its discovery potential to a host of new particles,
including dark photons, axion-like particles, and other CP-odd scalars. A FLUKA
simulation and analytical estimates have confirmed that numerous potential
backgrounds are highly suppressed at the FASER location, and the first in situ
measurements are currently underway. We describe FASER's location and discovery
potential, its target signals and backgrounds, the detector's layout and
components, and the experiment's preliminary cost estimate, funding, and
timeline