The Scattering and Neutrino Detector at the LHC (SND@LHC) started taking data at the beginning of Run 3 of the LHC. The experiment is designed to perform measurements with neutrinos produced in ...proton-proton collisions at the LHC in an energy range between 100 GeV and 1 TeV. It covers a previously unexplored pseudo-rapidity range of
7.2
<
η
<
8.4
. The detector is located 480 m downstream of the ATLAS interaction point in the TI18 tunnel. It comprises a veto system, a target consisting of tungsten plates interleaved with nuclear emulsion and scintillating fiber (SciFi) trackers, followed by a muon detector (UpStream, US and DownStream, DS). In this article we report the measurement of the muon flux in three subdetectors: the emulsion, the SciFi trackers and the DownStream Muon detector. The muon flux per integrated luminosity through an 18
×
18 cm
2
area in the emulsion is:
1.5
±
0.1
(
stat
)
×
10
4
fb/cm
2
.
The muon flux per integrated luminosity through a 31
×
31 cm
2
area in the centre of the SciFi is:
2.06
±
0.01
(
stat
)
±
0.12
(
sys
)
×
10
4
fb/cm
2
The muon flux per integrated luminosity through a 52
×
52 cm
2
area in the centre of the downstream muon system is:
2.35
±
0.01
(
stat
)
±
0.10
(
sys
)
×
10
4
fb/cm
2
The total relative uncertainty of the measurements by the electronic detectors is 6
%
for the SciFi and 4
%
for the DS measurement. The Monte Carlo simulation prediction of these fluxes is 20–25
%
lower than the measured values.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract SND@LHC is a compact and stand-alone experiment designed to perform measurements with neutrinos produced at the LHC in the pseudo-rapidity region of 7.2 < η < 8.4. The experiment is located ...480 m downstream of the ATLAS interaction point, in the TI18 tunnel. The detector is composed of a hybrid system based on an 830 kg target made of tungsten plates, interleaved with emulsion and electronic trackers, also acting as an electromagnetic calorimeter, and followed by a hadronic calorimeter and a muon identification system. The detector is able to distinguish interactions of all three neutrino flavours, which allows probing the physics of heavy flavour production at the LHC in the very forward region. This region is of particular interest for future circular colliders and for very high energy astrophysical neutrino experiments. The detector is also able to search for the scattering of Feebly Interacting Particles. In its first phase, the detector is ready to operate throughout LHC Run 3 and collect a total of 250 fb -1 .
After rapid approval and installation, the SND@LHC Collaboration was able to gather data successfully in 2022 and 2023. Neutrino interactions from νμs originating at the LHC IP1 were observed. Since ...muons constitute the major background for neutrino interactions, the muon flux entering the acceptance was also measured. To improve the rejection power of the detector and to increase the fiducial volume, a third Veto plane was recently installed. The energy resolution of the calorimeter system was measured in a test beam. This will help with the identification of νe interactions that can be used to probe charm production in the pseudo-rapidity range of SND@LHC (7.2 < η < 8.4). Events with three outgoing muons have been observed and are being studied. With no vertex in the target, these events are very likely from muon trident production in the rock before the detector. Events with a vertex in the detector could be from trident production, photon conversion, or positron annihilation. To enhance SND@LHC’s physics case, an upgrade is planned for HL-LHC that will increase the statistics and reduce the systematics. The installation of a magnet will allow the separation of νμ from ν¯μ
The CMS muon barrel drift tubes system commissioning Abbiendi, G.; Amapane, N.; Battilana, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2009, 2009-1-00, Letnik:
598, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The CMS muon barrel drift tubes system has been recently fully installed and commissioned in the experiment. The performance and the current status of the detector are briefly presented and discussed.
Two drift tubes (DTs) chambers of the CMS muon barrel system were exposed to a 40
MHz bunched muon beam at the CERN SPS, and for the first time the whole CMS Level-1 DTs-based trigger system chain ...was tested. Data at different energies and inclination angles of the incident muon beam were collected, as well as data with and without an iron absorber placed between the two chambers, to simulate the electromagnetic shower development in CMS. Special data-taking runs were dedicated to test for the first time the Track Finder system, which reconstructs track trigger candidates by performing a proper matching of the muon segments delivered by the two chambers. The present paper describes the results of these measurements.
Most distributed applications are based on architectural models that do not involve real-time knowledge of network status and of their network usage. Moreover the new “network aware” architectures ...are still under development and their design is not yet complete. We considered, as a use case, an application using ODBMS (Objectivity/DB) for the distributed analysis of experimental data. The dynamic usage of system and network resources at host and application levels has been measured in different client/server configurations, and on several LAN and WAN layouts. The aim was to study the application efficiency and behavior versus the network characteristics and conditions.
The most interesting results of the LAN and WAN tests are described. System bottlenecks and limitations have been identified, and efficient working conditions in the different scenarios have been defined. The behavior observed when moving away from the optimal working conditions is also described.
The objective of the MONARC project is to identify baseline computing models that could provide viable solutions meeting the data analysis needs of the LHC experiments. A powerful and flexible set of ...simulation tools has been developed to model the performance of distributed computing resources for a set of reconstruction and analysis tasks. In this paper we report the validation of the simulation tools using the testbed environments with Objectivity/DB over LAN and WAN connections. A simple and effective way to parameterize and evaluate the concurrent database access over network has been established.
We present an observation at LEP of the production of
χ
c2 mesons in the collisions of two quasi-real photons using the OPAL detector. The
χ
c2 mesons are reconstructed in the decay channel
χ
c2
→J/ψ
...γ→ℓ
+
ℓ
−
γ
(with ℓ =
e,
μ) using all data taken at e
+e
− centre-of-mass energies of 91 and 183 GeV, corresponding to integrated luminosities of 167 and 55 pb
−1 respectively. The two-photon width of the
χ
c2 is determined to be
Γ(
χ
c2→
γγ)=1.76±0.47±0.37±0.15 keV, where the first error is statistical, the second is systematic and the third comes from branching ratio uncertainties.
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