Candan Dozen

Abstract 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 $$\nu $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ν</mml:mi></mml:math> , 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 $$\nu $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ν</mml:mi></mml:math> detector, and analyze the characteristics of the signals and primary backgrounds. For an integrated luminosity of $$150~\text {fb}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>150</mml:mn><mml:mspace /><mml:msup><mml:mtext>fb</mml:mtext><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> to be collected during Run 3 of the 14 TeV LHC in 2021–23, approximately 1300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASER $$\nu $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ν</mml:mi></mml:math> , 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.

$\mathrm{FASER}\ensuremath{\nu}$ 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 $12.2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ 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.

The FASER experiment at the LHC is designed to search for light, weakly-interacting particles produced in proton-proton collisions at the ATLAS interaction point that travel in the far-forward direction. The first results from a search for dark photons decaying to an electron-positron pair, using a dataset corresponding to an integrated luminosity of 27.0 fb$^{-1}$ collected at center-of-mass energy $\sqrt{s} = 13.6$ TeV in 2022 in LHC Run 3, are presented. No events are seen in an almost background-free analysis, yielding world-leading constraints on dark photons with couplings $ε\sim 2 \times 10^{-5} - 1 \times 10^{-4}$ and masses $\sim$ 17 MeV - 70 MeV. The analysis is also used to probe the parameter space of a massive gauge boson from a U(1)$_{B-L}$ model, with couplings $g_{B-L} \sim 5 \times 10^{-6} - 2 \times 10^{-5}$ and masses $\sim$ 15 MeV - 40 MeV excluded for the first time.

FASER is a new experiment designed to search for new light weakly-interacting long-lived particles (LLPs) and study high-energy neutrino interactions in the very forward region of the LHC collisions at CERN. The experimental apparatus is situated 480 m downstream of the ATLAS interaction-point aligned with the beam collision axis. The FASER detector includes four identical tracker stations constructed from silicon microstrip detectors. Three of the tracker stations form a tracking spectrometer, and enable FASER to detect the decay products of LLPs decaying inside the apparatus, whereas the fourth station is used for the neutrino analysis. The spectrometer has been installed in the LHC complex since March 2021, while the fourth station is not yet installed. FASER will start physics data taking when the LHC resumes operation in early 2022. This paper describes the design, construction and testing of the tracking spectrometer, including the associated components such as the mechanics, readout electronics, power supplies and cooling system.

Abstract The FASER experiment is a new small and inexpensive experiment that is placed 480 meters downstream of the ATLAS experiment at the CERN LHC. FASER is designed to capture decays of new long-lived particles, produced outside of the ATLAS detector acceptance. These rare particles can decay in the FASER detector together with about 500–1000 Hz of other particles originating from the ATLAS interaction point. A very high efficiency trigger and data acquisition system is required to ensure that the physics events of interest will be recorded. This paper describes the trigger and data acquisition system of the FASER experiment and presents performance results of the system acquired during initial commissioning.

FASERnu is a proposed small and inexpensive emulsion detector designed to detect collider neutrinos for the first time and study their properties. FASERnu will be located directly in front of FASER, 480 m from the ATLAS interaction point along the beam collision axis in the unused service tunnel TI12. From 2021-23 during Run 3 of the 14 TeV LHC, roughly 1,300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASERnu with TeV-scale energies. With the ability to observe these interactions, reconstruct their energies, and distinguish flavors, FASERnu will probe the production, propagation, and interactions of neutrinos at the highest human-made energies ever recorded. The FASERnu detector will be composed of 1000 emulsion layers interleaved with tungsten plates. The total volume of the emulsion and tungsten is 25cm x 25cm x 1.35m, and the tungsten target mass is 1.2 tonnes. From 2021-23, 7 sets of emulsion layers will be installed, with replacement roughly every 20-50 1/fb in planned Technical Stops. In this document, we summarize FASERnu's physics goals and discuss the estimates of neutrino flux and interaction rates. We then describe the FASERnu detector in detail, including plans for assembly, transport, installation, and emulsion replacement, and procedures for emulsion readout and analyzing the data. We close with cost estimates for the detector components and infrastructure work and a timeline for the experiment.

FASERnu is a proposed small and inexpensive emulsion detector designed to detect collider neutrinos for the first time and study their properties. FASERnu will be located directly in front of FASER, 480 m from the ATLAS interaction point along the beam collision axis in the unused service tunnel TI12. From 2021-23 during Run 3 of the 14 TeV LHC, roughly 1,300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASERnu with TeV-scale energies. With the ability to observe these interactions, reconstruct their energies, and distinguish flavors, FASERnu will probe the production, propagation, and interactions of neutrinos at the highest human-made energies ever recorded. The FASERnu detector will be composed of 1000 emulsion layers interleaved with tungsten plates. The total volume of the emulsion and tungsten is 25cm x 25cm x 1.35m, and the tungsten target mass is 1.2 tonnes. From 2021-23, 7 sets of emulsion layers will be installed, with replacement roughly every 20-50 1/fb in planned Technical Stops. In this document, we summarize FASERnu's physics goals and discuss the estimates of neutrino flux and interaction rates. We then describe the FASERnu detector in detail, including plans for assembly, transport, installation, and emulsion replacement, and procedures for emulsion readout and analyzing the data. We close with cost estimates for the detector components and infrastructure work and a timeline for the experiment.

Studies of high energy proton interactions have been basic inputs to understand the cosmic-ray spectra observed on the earth.Yet, the experimental knowledge with controlled beams has been limited.In fact, uncertainties of the forward hadron production are very large due to the lack of experimental data.The FASER experiment is proposed to measure particles, such as neutrinos and hypothetical dark-sector particles, at the forward location of the 14 TeV proton-proton collisions at the LHC.As it corresponds to 100-PeV proton interactions in fixed target mode, a precise measurement by FASER would provide information relevant for PeV-scale cosmic rays.By studying three flavor neutrinos with the dedicated neutrino detector (FASER ), FASER will lead to a quantitative understanding of prompt neutrinos, which is an important background towards the astrophysical neutrino observation by neutrino telescopes such as IceCube.In particular, the electron and tau neutrinos have strong links with charmed hadron production.And, the FASER measurements may also shed light on the unresolved muon puzzle at the high energy.FASER is going to start taking data in 2022.We expect about 8000 numu, 1300 nue and 20 nutau CC interactions at the TeV energy scale during Run 3 of the LHC operation (2022-2024) with a 1.1 tons emulsion-based neutrino detector.We report here the overview and prospect of the FASER experiment in relation to the cosmic-ray physics, together with the first LHC neutrino candidates that we caught in the pilot run held in 2018.

In 2014 CERN has started to organize "Beamline for Schools" (BL4S), an annual physics competition for high-school students aged 16 or more.In the competition, teams of students from all around the world are invited to propose an experiment to CERN that makes use of a secondary beam of particles with momenta of up to 10 GeV/c from CERN's Proton Synchrotron.In the first four years of the competition, 6900 students from all around the world have participated and in total eight winning teams have been selected and invited to CERN for ten to twelve days each.We will describe the challenges linked to the Beamline for Schools competition, focussing on the communication with all teams in the preparatory phase of the competition, the technical implementation of the winning experiments, the operation of the experiments as well as on the support for the teams analysing the data and preparing publications of the results.We will also report on the impact of the competition on the candidate teams as well as on the winners.Finally, we will present an outlook for the future of the BL4S competition, taking into account the shutdown of the accelerators at CERN in 2019 and 2020.

The FASER experiment is a new small and inexpensive experiment that is located 480 meters downstream of the ATLAS experiment at the CERN LHC.The experiment will shed light on currently unexplored phenomena, having the potential to make a revolutionary discovery.FASER is designed to capture decays of exotic particles, produced in the very forward region, beyond the ATLAS detector acceptance.The experiment installation was completed at the end of March 2021 and the experiment is now getting ready for the LHC Run 3 data-taking.This presentation will focus mostly on the trigger and data acquisition (TDAQ) system of the experiment.The TDAQ system is going to combine information from the tracker, scintillators, and calorimeter and will send them to the PC that is going to be located on the ground at the expected physics trigger rate of 650 Hz.The presentation will include information about the commissioning of the system on the ground and in the LHC tunnel as well as it will be presenting various tests performed during the commissioning phase including first test runs using cosmic particles.

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$\nu$, 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.

CERN Beamline for Schools is an annual worldwide competition for high-school students.Teams of students are invited to propose an experiment with one of the secondary beams of the Proton Synchrotron and two winning experiments are performed each year by students with a help of CERN experts.We will describe detectors available to students, with emphasis on design and performance of recently added Multi-Gap Resistive Plate Chambers and MicroMegas chambers which were constructed in collaboration with CERN detector experts.

Although the Standard Model successfully explains most phenomena at the LHC, there are several outstanding questions, including the nature of dark matter, the origin of neutrino masses, and the asymmetry in matter and anti-matter abundances in the Universe.Located in the side tunnel TI12, the Forward Search Experiment (FASER) will search for highly displaced signals from light and extremely weakly interacting particles that can be copiously produced in proton-proton collisions at the LHC.After their production at the ATLAS interaction point, light long-lived particles move along the beam collision axis line of sight, and then may decay within the volume of FASER into visible Standard Model particles.During the current long shutdown, the FASER experiment will complete the hardware and software module production and commissioning and be installed underground.In Run 3 during 2021-2024, the FASER detector will start taking data.Tsinghua University team produced the Tracker Interlock and Monitoring (TIM) board and the MPOD Interlock (MPODI) board to monitor the condition of the FASER tracker stations.If the temperature exceeds the normal range, the TIM board will send a hardware interlock signal to the LV and HV power supply, and the power supply will be turned off to protect the tracker station.Temperature and humidity data read from TIM will also be sent to DCS for further processing.MPODI monitors the status of chiller and controls the MPOD.

FASER$\nu$ 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$^{-1}$ 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.