Over the last years, radio detection has matured to become a competitive method for the detection of air showers. Arrays of thousands of antennas are now envisioned for the detection of cosmic rays ...of ultra high energy or neutrinos of astrophysical origin. The data exploitation of such detectors requires to run massive air-shower simulations to evaluate the radio signal at each antenna position. In order to reduce the associated computational cost, we have developed a semi-analytical method for the computation of the emitted radio signal called Radio Morphing. The method consists in computing the radio signal of any air-shower at any location from the simulation of one single reference shower at given positions by (i) a scaling of the electric-field amplitude of this reference shower, (ii) an isometry on the simulated positions and (iii) an interpolation of the radio pulse at the desired position. This technique enables one to compute electric field time traces with characteristics very similar to those obtained with standard computation methods, but with computation times reduced by several orders of magnitude. In this paper, we present this novel tool, explain its methodology, and discuss its limitations. Furthermore, we validate the method on a typical event set for the future GRAND experiment showing that the calculated peak amplitudes are consistent with the results from ZHAireS simulations with a mean offset of +8.5% and a standard deviation of 27.2% in this specific case. This overestimation of the signal strength by Radio Morphing arises mainly from the choice of the underlying reference shower.
The LHCb calorimeter system consists of a Scintillating Pad Detector (SPD), a PreShower detector (PS) followed by electromagnetic (ECAL) and hadronic (HCAL) calorimeters. The LHCb preshower detector ...provides the longitudinal segmentation of the electromagnetic shower detection. It is located immediately upstream from the ECAL, with one-to-one correspondence between ECAL towers, SPD and preshower cells. The PS detector is part of the first level of the LHCb trigger system (called Level-0). It is used in conjunction with the SPD, ECAL and HCAL to search for clusters of 2 × 2 cells and to identify e, γ, π°, hadron of highest ET. This contribution discusses the requirements for the synchronisation and calibration of the PS detector, as well as the methods that were used to determine the first settings before the LHC start-up. The methods used to perform the fine synchronisation and calibration once LHC collisions were available are introduced, and the precisions that were obtained are given.
We discuss tests of the charged Higgs sector of the Two Higgs Doublet Model (2HDM) of Type II in the light of recent flavour physics data. Particular attention is paid to recent measurement of purely ...leptonic decays of heavy-light mesons, which depart more or less significantly from the Standard Model (SM) predictions. We derive constraints on the parameters of the 2HDM type II from leptonic and semileptonic $\Delta F=1$ decays as well as loop processes ($b \to s \gamma$ or $Z\to\bar{b}b$) sensitive to charged Higgs contributions. The outcome of this work is that while 2HDM Type II can fit individual observable through fine-tuning schemes, in a combined analysis it does not perform better than the SM by favouring a decoupling solution. Assuming that 2HDM Type II is realized in Nature, constraints on its parameters ($m_{H^+}$ and $\tan \beta$) are derived. A limit on the charged Higgs mass $m_{H^+} > 304 {\rm GeV}$ at 95% CL is obtained irrespective of the value of $\tan \beta$. This limit is dominated by the $b\to s \gamma$ branching ratio measurement. All results have been obtained with the \ckmfitter analysis package, featuring the frequentist statistical approach \rfit to handle theoretical uncertainties.
SUMMARY
Muography is a relatively new geophysical imaging method that uses muons to provide estimates of average densities along particular lines of sight. Muography can only see above the horizontal ...elevation of the detector and it is therefore attractive to attempt a joint inversion of muography data with gravity data, which is also responsive to density but generally requires combination with another geophysical data set to overcome issues related to non-uniqueness and poor depth resolution. Some previous work has investigated this joint inverse problem and demonstrated the potential improvements to be gained by jointly inverting muography and gravity data. However, there has yet to be a thorough investigation of different numerical approaches for formulating the joint inverse problem. Particularly important is how to account for the fact that even though the two data types are sensitive to the same physical quantity, density, they respond through different response functions. Moreover, the two measurements are affected by different systematic uncertainties that are difficult to model. In this work, we considered an approximation where the two density quantities, inferred from the two data types, can be related by an unknown scalar offset. We considered various existing and new joint inversion methods that might solve this problem and we applied them to a synthetic volcano imaging scenario based on the Puy de Dôme volcano in the Central Massif region of France. We used unstructured meshes in our modelling to adequately honour the significant topography in that scenario. Our experiments indicated that the most successful joint inversion method for this type of geological scenario was one in which the data misfit function is reformulated to automatically determine the best-fitting offset following a least-squares minimization argument. However, other approaches showed merit and we suggest several of the investigated methods be applied and compared for any specific joint inversion scenario.
Tau neutrinos in the next decade: from GeV to EeV Abraham, Roshan Mammen; Alvarez-Muñiz, Jaime; Argüelles, Carlos A ...
Journal of physics. G, Nuclear and particle physics,
11/2022, Letnik:
49, Številka:
11
Journal Article
We present an algorithm for simulating reverse Monte Carlo decays given an existing forward Monte Carlo decay engine. This algorithm is implemented in the Alouette library, a TAUOLA thin wrapper for ...simulating decays of tau-leptons. We provide a detailed description of Alouette, as well as validation results.
The PUMAS library Niess, Valentin
arXiv.org,
06/2022
Paper, Journal Article
Odprti dostop
The PUMAS library is a transport engine for muon and tau leptons in matter. It can operate with a configurable level of details, from a fast deterministic CSDA mode to a detailed Monte~Carlo ...simulation. A peculiarity of PUMAS is that it is revertible, i.e. it can run in forward or in backward mode. Thus, the PUMAS library is particularly well suited for muography applications. In the present document, we provide a detailed description of PUMAS, of its physics and of its implementation.
A preliminary version (v0.2.1) of the DANTON Monte-Carlo package is
presented. DANTON allows the exclusive sampling of (decaying) $\tau$ generated
by $\nu_\tau$ interactions with the Earth. The ...particles interactions with
matter are simulated in detail, including transverse scattering. Detailed
topography data of the Earth can be used as well. Yet, high Monte-Carlo
efficiency is achieved by using a Backward Monte-Carlo technique. Some
validation results are provided.
TURTLE is a C library providing utilities allowing to navigate through a topography described by a Digital Elevation Model (DEM). The library has been primarily designed for the Monte Carlo transport ...of particles scattering over medium to long ranges, e.g. atmospheric muons. But, it can also efficiently handle ray tracing problems with very large DEMs (\(10^9\) nodes or more), e.g. for neutrino simulations. The TURTLE library was built on an optimistic ray tracing algorithm, detailed in the present paper. This algorithm proceeds by trials and errors, approximating the topography within the modelling uncertainties of the DEM data. This allows to traverse a topography in constant time, i.e. independently of the number of grid nodes, and with no added memory. Detailed performance studies are provided by comparison to other ray tracing algorithms and as an application to muon transport in a Monte Carlo simulation.
A preliminary version (v0.2.1) of the DANTON Monte-Carlo package is presented. DANTON allows the exclusive sampling of (decaying) \(\tau\) generated by \(\nu_\tau\) interactions with the Earth. The ...particles interactions with matter are simulated in detail, including transverse scattering. Detailed topography data of the Earth can be used as well. Yet, high Monte-Carlo efficiency is achieved by using a Backward Monte-Carlo technique. Some validation results are provided.
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