Search

The Muon g-2 Experiment at Fermi National Accelerator Laboratory was designed to measure the anomalous magnetic moment of the muon, aμ, with a precision of 140 parts-per-billion; a four-fold improvement over the former BNL measurement. The Fermilab experiment was motivated by the about 3.5 standard deviation between the experiment and the Standard Model calculation of aμ which could be a hint of new physics. The experiment at Fermilab relies on the well-established storage ring technique using magic momentum muons but employs new detector systems and a higher rate of muons per injection cycle to achieve the significant improvement in precision. A first result from the Run-1 data taking period has achieved an uncertainty of 0.46 parts-per-million and confirmed the BNL discrepancy, further increasing the tension with the Standard Model to 4.2σ. The experimental technique, key aspects of the measurement, and the data analysis of Run-1 will be summarized. [ABSTRACT FROM AUTHOR]

Triggered data acquisition systems provide only limited possibilities of triggering methods. In our paper, we propose a novel approach that completely removes the hardware trigger and its logic. It introduces an innovative free-running mode instead, which provides unprecedented possibilities to physics experiments. We would like to present such system, which is being developed for the AMBER experiment at CERN. It is based on an intelligent data acquisition framework including FPGA modules and advanced software processing. The system provides a triggerless mode that allows more time for data filtering and implementation of more complex algorithms. Moreover, it utilises a custom data protocol optimized for needs of the free-running system. The filtering procedure takes place in a server farm playing the role of the highlevel trigger. For this purpose, we introduce a high-performance filtering framework providing optimized algorithms and load balancing to cope with excessive data rates. Furthermore, this paper also describes the filter pipeline as well as the simulation chain that is being used for production of artificial data, for testing, and validation. [ABSTRACT FROM AUTHOR]

This paper presents a graph neural network (GNN) technique for low-level reconstruction of neutrino interactions in a Liquid Argon Time Projection Chamber (LArTPC). GNNs are still a relatively novel technique, and have shown great promise for similar reconstruction tasks in the LHC. In this paper, a multihead attention message passing network is used to classify the relationship between detector hits by labelling graph edges, determining whether hits were produced by the same underlying particle, and if so, the particle type. The trained model is 84% accurate overall, and performs best on the EM shower and muon track classes. The model's strengths and weaknesses are discussed, and plans for developing this technique further are summarised. [ABSTRACT FROM AUTHOR]

A surface array of radio antennas will enhance the performance of the IceTop array and enable new, complementary science goals. First, the accuracy for cosmic-ray air showers will be increased since the radio array provides a calorimetric measurement of the electromagnetic component and is sensitive to the position of the shower maximum. This enhanced accuracy can be used to better measure the mass composition, to search for possible mass-dependent anisotropies in the arrival directions of cosmic rays, and for more thorough tests of hadronic interaction models. Second, the sensitivity of the radio array to inclined showers will increase the sky coverage for cosmic-ray measurements. Third, the radio array can be used to search for PeV photons from the Galactic Center. Since IceTop is planned to be enhanced by a scintillator array in the near future, a radio extension sharing the same infrastructure can be installed with minimal additional effort and excellent scientific prospects. The combination of ice-Cherenkov, scintillation, and radio detectors at IceCube will provide unprecedented accuracy for the study of highenergy Galactic cosmic rays. [ABSTRACT FROM AUTHOR]

The cross section of the process e+e−→ π+π−π+π− has been measured using an integrated luminosity of 17 pb−1 collected with the CMD-3 detector in the center-of-mass energy range 650-1000 MeV. High-precision measurements of various hadronic cross sections are of great interest in relation with the problem of the muon anomalous magnetic moment g-2. This measurement can be also used to test the relation between the cross section of e+e−→ π+ π−π+ π− and the spectral function for the τ−→ π−π0π0π0 decay predicted by the conservation of vector current (CVC). [ABSTRACT FROM AUTHOR]

Early results of the search for Eγ > 1 PeV cosmic photons from point sources with the data of Carpet–2, an air-shower array equipped with a 175 m2 muon detector, are presented. They include 95% CL upper limits on PeV photon fluxes from stacked directions of high-energy IceCube neutrino events and from four predefined sources, Crab, Cyg X-3, Mrk 421 and Mrk 501. An insignificant excess of events from Mrk 421 will be further monitored. Prospects of the use of the upgraded installation, Carpet–3 (410 m2 muon detector), scheduled to start data taking in 2019, for searches of Eγ > 100 TeV photons, are briefly discussed. [ABSTRACT FROM AUTHOR]

The Pierre Auger Observatory represents the largest effort undertaken by scientists to observe high energy cosmic rays by recording the information available in extensive air showers (EAS). The Observatory consists of several detection systems: the water Cherenkov detectors (covering an area of 3000 km²), the fluorescence detectors (overlooking the entire Cherenkov array), and the smaller systems: the radio antenna array (currently covering 17 km²) and the muon underground detectors. This hybrid approach facilitates the observation of a single shower from multiple points of view. Thus various parameters can be reconstructed and validated with several measurements. The physics at the Observatory focuses on mass composition, energy spectrum and sources of the primary astropaticles, as well as atmospheric and detectors studies. The recent discoveries of the Observatory have helped us understand the Universe at these ultra high energies, unavailable to terrestrial accelerators. [ABSTRACT FROM AUTHOR]

This talk is about the hadronic light-by-light contribution to the muon anomalous magnetic moment, mainly our old work but including some newer results as well. It concentrates on the model calculations. Most attention is paid to pseudo-scalar exchange and the pion loop contribution. Scalar, a1-exchange and other contributions are shortly discussed as well. For the π0;-exchange a possible large cancellation between connected and disconnected diagrams is expected. [ABSTRACT FROM AUTHOR]

Systematic studies on the GEM foil material are performed to measure the moisture diffusion rate and saturation level. These studies are important because the presence of this compound inside the detector's foil can possibly change its mechanical and electrical properties, and in such a way, the detector performance can be affected. To understand this phenomenon, a model is developed with COMSOL Multiphysics v. 4.3 [1], which described the adsorption and diffusion within the geometry of GEM foil, the concentration profiles and the time required to saturate the foil. The COMSOL model is verified by experimental observations on a GEM foil sample. This note will describe the model and its experimental verification results. [ABSTRACT FROM AUTHOR]

In view of the use of Micromegas detectors for the upgrade of the ATLAS muon system, two detector quadruplets with an area of 0.3 m² per plane serving as prototypes for future ATLAS chambers have been constructed. They are based on the resistive-strip technology and thus spark tolerant. The detectors were built in a modular way. The quadruplets consist of two double-sided readout panels and three support (or drift) panels equipped with the micromesh and the drift electrode. The panels are bolted together such that the detector can be opened and cleaned, if required. Two of the readout planes are equipped with readout strips inclined by 1.5 degree. In this talk, we present the results of detailed performance studies based on X-Ray and cosmic ray measurements as well as measurements with 855 MeV electrons at the MAMI accelerator. In particular, results on reconstruction efficiencies, track resolution and gain homogeneity is presented. [ABSTRACT FROM AUTHOR]

In 2015 the first full size resistive-strip Micromegas modules for the ATLAS New Small Wheel upgrade will be realized. The goal is to provide precision muon tracking with spatial resolution below 100 µm on trapezoidal four-layer detector modules with areas between 2 and 3 m². This poses stringent limits on the overall accuracy of the modules with respect to strip positioning and planarity. Each module is built as a quadruplet of four resistive strip Micromegas layers, constructed from stiff sandwich panels. An assembly procedure has been developed to build the panels and modules with the required mechanical precision of 30 µm along the precision coordinate and 80 µm perpendicular to the chamber. The construction and quality assurance procedures ensure good module quality verified by checks done during the construction and the chamber assembly. [ABSTRACT FROM AUTHOR]

Recently the CERN ALICE experiment, in its dedicated cosmic ray run, observed muon bundles of very high multiplicities, thereby confirming similar findings from the LEP era at CERN (in the CosmoLEP project). We found significant evidence for anisotropy of arrival directions of the observed high multiplicity muonic bundles. The distribution on celestial sphere and the estimated directionality suggests their possible extragalactic source. We argue that muonic bundles of highest multiplicity are produced by strangelets, hypothetical stable lumps of strange quark matter infiltrating our Universe. [ABSTRACT FROM AUTHOR]

The Pierre Auger Observatory is the largest observatory for the detection of cosmic rays. With the Auger Engineering Radio Array (AERA) we measure the emitted radio signal of extensive air showers and reconstruct properties of the primary cosmic rays. For horizontal air showers (zenith angles larger than 60°) the signal is distributed over a large area of more than several km2. Therefore, detection of air showers using a sparse radio antenna array, compatible with the 1500 m distance between the 1600 surface detector stations, is possible. The radio technique is sensitive to the electromagnetic component of air showers. Combining radio detection with particle information from the surface detector of the Observatory, which at large zenith angles mostly detects muons, allows to study the cosmic ray composition for horizontal air showers. [ABSTRACT FROM AUTHOR]

A major upgrade of the readout and trigger electronics of the CMS Drift Tubes muon detector is foreseen in order to allow its efficient operation at the High Luminosity LHC. A proposal for a new L1 Trigger Primitives Generator for this detector is presented, featuring an algorithm operating on the time of charge collection measurements provided by the asynchronous readout of the new TDC system being developed. The algorithm is being designed around the implementation in state-of-the-art FPGA devices of the original development of a Compact Hough Transform (CHT) algorithm combined with a Majority Mean-Timer, to identify both the parent bunch crossing and the muon track parameters. The current state of the design is presented along with the performance requirements, focusing on the future developments. [ABSTRACT FROM AUTHOR]

The μ- +3 He → νμ + n + d and μ- +3 He → νμ + n + n + p capture reactions are studied under full inclusion of final state interactions with the AV18 nucleon-nucleon potential, augmented by the Urbana IX three-nucleon force, and employing the single nucleon weak current operator. We give first realistic estimates of the total capture rates: 544 s-1 and 154 s-1 for the n + d and n + n + p channels, respectively. Our results are compared with the most recent experimental data, finding a rough agreement for the total capture rates, but failing to reproduce the differential capture rates. [ABSTRACT FROM AUTHOR]

The future KM3NeT neutrino telescope will consist of several thousand digital optical modules (DOMs), each of which will be equipped with 31 3-inch photo-multiplier tubes (PMTs). This design has various advantages over the use of one large PMT per optical module, e.g. concerning effective photocathode area per module, improved background suppression and directional reconstruction. Currently, the KM3NeT collaboration is testing a prototype DOM deployed on the instrumentation line of the ANTARES neutrino telescope. The DOM has been operational since mid-April 2013. First data are presented and compared to simulation results. The results are very encouraging and indicate that muon identification and a coarse direction estimation are possible event with a single DOM. [ABSTRACT FROM AUTHOR]

A new trigger for NEMO Phase 2 tower based on the time differences of the PMT hits has been studied. Such a trigger uses only a fixed number of PMT hits in a chosen time windows. The background trigger rate is drastically reduced requiring hits from different PMTs. A 87% trigger efficiency was estimated by Montecarlo simulation for muon tracks with at least 5 PMT hits. The trigger rate estimated by Montecarlo was also measured on raw data. The results from Montecarlo simulations and raw data are reported. [ABSTRACT FROM AUTHOR]

Might a nuclear-armed terrorist group or state use ordinary commerce to deliver a nuclear weapon by smuggling it in a cargo container or vehicle? This delivery method would be the only one available to a sub-state actor, and it might enable a state to make an unattributed attack. Detection of a weapon or fissile material smuggled in this manner is difficult because of the large volume and mass available for shielding. Here I review methods for screening cargo containers to detect the possible presence of nuclear threats. Because of the large volume of innocent international commerce, and the cost and disruption of secondary screening by opening and inspection, it is essential that the method be rapid and have a low false-positive rate. Shielding can prevent the detection of neutrons emitted spontaneously or by induced fission. The two promising methods are muon tomography and high energy X-radiography. If they do not detect a shielded threat object they can detect the shield itself. [ABSTRACT FROM AUTHOR]

The results of the search for the Standard Model (SM) Higgs Boson with the CMS detector in proton-proton collisions at the LHC at 7 TeV center-of-mass energy are reported. A large number of the Higgs Boson decay channels in the mass range from 110 GeV to 600 GeV are considered, and combined upper limits on the production cross section as a function of the Higgs Boson mass are derived. The SM Higgs is excluded at 95% confidence level in the mass range between 127.5 GeV and 600 GeV. In addi- tion, searches for Higgs Bosons in scenarios Beyond the Standard Model (BSM) lead to improved constraints on the Higgs sector of BSM theories such as supersymmetry. [ABSTRACT FROM AUTHOR]

The findings so far of the Pierre Auger Observatory and also of the Telescope Array define the requirements for a possible next generation experiment: it needs to be considerably increased in size, it needs a better sensitivity to composition, and it should cover the full sky. AugerNext aims to perform innovative research studies in order to prepare a proposal fulfilling these demands. Such R&D studies are primarily focused in the following areas i) consolidation of the detection of cosmic rays using MHz radio antennas; ii) proof-of-principle of cosmic-ray microwave detection; iii) test of the large-scale application of a new generation photo-sensors; iv) generalization of data communication techniques; v) development of new ways of muon detection with surface arrays. These AugerNext studies on new innovative detection methods for a next generation cosmic-ray experiment are performed at the Pierre Auger Observatory. The AugerNext consortium consists presently of fourteen partner institutions from nine European countries supported by a network of European funding agencies and it is a principal element of the ASPERA/ApPEC strategic roadmaps. [ABSTRACT FROM AUTHOR]

The results of the Yakutsk array experiment aimed at investigations of ultra-high energy cosmic rays (UHECRs) are presented. We outline the current status of the instrument and an outlook for future directions and areas of study. [ABSTRACT FROM AUTHOR]

We describe two setups that were built for low-background gamma-ray spectrometry in the Garching Underground Laboratory (∼ 10 m.w.e.). Both setups are based on HPGe detectors surrounded by several layers of passive shielding as well as an active muon veto. The first setup (GEM) comprises a single HPGe detector surrounded by a NaI(Tl) scintillation detector that serves as anti-Compton veto. The second setup (LoAx) consists of two smaller HPGe detectors which are arranged face-to-face to cover a large solid angle around the sample. The detection efficiency of both systems is determined using a calibrated Monte-Carlo simulation. The count rate finally achieved in the energy range 40-2700keV is 10250±26cts/day for the GEM setup, and 5258±27cts/day and 6876±31cts/day between 20-1500keV for the two detectors of the LoAx setup. This leads to detection sensitivities of a few mBq/kg for U and Th at both screening stations. [ABSTRACT FROM AUTHOR]

The ceiling and walls of the Low Background Facility at the Soudan Underground Laboratory are lined proportional tubes which form a 30 m × 17 m ×12 m muon tracker. The data acquisition records GPS-generated time stamps along with position information. The tracker is a refurbished version of the Soudan 2 proton-decay muon veto shield. It can now be used in conjunction with other experiments housed within its walls. Particularly interesting is the possible measurement of cavern muons coincident with high-energy neutron detections in the Neutron Multiplicity Meter (NMM), a 4-tonne gadolinium-loaded water Cherenkov neutron capture detector atop a 20-kilotonne lead target. Here we cover the ability of the shield and co-located detectors to achieve coincident timing resolutions of about 1 microsecond via GPS-synchronized absolute timing electronics. The usage of such technology for constraining muon-neutron correlations underground is discussed. [ABSTRACT FROM AUTHOR]

The Cosmic Ray Inspection and Passive Tomography (CRIPT) project has recently started investigating the detection of illicit Special Nuclear Material in cargo using cosmic ray muon tomography and complementary neutron detectors. We are currently performing simulation studies to help with the design of small scale prototypes. Based on the prototype tests and refined simulations, we will determine whether the muon tracking system for the full scale prototype will be based on drift chambers or extruded scintillator trackers. An analysis of the operations of the Port of Montreal has determined how long muon scan times should take if all or a subset of the cargo is to be screened. As long as the throughput of the muon system(s) is equal to the rate at which containers are unloaded from ships, the impact on port operations would not be great if a muon scanning stage were required for all cargo. We also show preliminary simulation results indicating that excellent separation between Al, Fe and Pb is possible under ideal conditions. The discrimination power is reduced but still significant when realistic momentum resolution measurements are considered. [ABSTRACT FROM AUTHOR]