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E. Spedicato

Publications and source records attributed to E. Spedicato.

9 recordsLinked to original sources
arXiv2026

Operation and performance of the Probe for Luminosity Measurement at LHCb

The Probe for LUminosity MEasurement (PLUME) detector is a dedicated luminosity monitor at the LHCb interaction point. It is a hodoscope comprising 48 Hamamatsu R760 photomultiplier tubes that detect Cherenkov light produced by particles travelling in the direction opposite to the LHCb spectrometer acceptance. PLUME provides real-time, bunch-by-bunch luminosity measurements during LHCb data taking and serves as the primary detector for controlling the luminosity levelling process at LHCb. In addition, its data are used offline, together with other dedicated counters from LHCb sub-systems, to determine the integrated luminosity delivered to the experiment. This paper reports on the detector's operational performance during the 2024-2026 data-taking period of Run 3. The integrated luminosity recorded by the LHCb experiment in $pp$ collisions at $\sqrt{s} = 13.6$ TeV during this period, as measured by the PLUME online luminosity counters for detector performance monitoring, amounts to $\mathcal{L} = (26.71 \pm 1.07)$ fb$^{-1}$. The luminosity values used in physics analyses are determined separately through dedicated offline calibrations based on van der Meer scans and Beam Gas Imaging techniques, and will be reported in a dedicated publication, as they are beyond the scope of this paper.

hep-ex↗
arXiv2024

A prototype electromagnetic calorimeter for the MUonE experiment: status and first performance results

The MUonE experiment proposes a novel approach to determine the leading hadronic contribution to the muon g-2, from a precise measurement of the differential cross section of the $μ-e$ elastic scattering, achievable by using the CERN SPS muon beam onto atomic electrons of a light target. The detector layout is modular, consisting of an array of identical tracking stations, each one made of a light target and silicon strip planes, followed by an electromagnetic calorimeter made of $PbWO_4$ crystals with APD readout, placed after the last station, and a muon filter. The scattering particles are tracked without any magnetic field, and the event kinematics can be defined in a large phase space region from the expected correlation of the outgoing particle angles. The ambiguity affecting a specific region, with electron and muon outgoing with similar deflection angles, can be solved by identifying the electron track as the one with extrapolation matching the calorimeter cluster or the muon track by associating it to hits in the muon filter. The role of the calorimeter will be important for background estimate and reduction, and to assess systematic errors, providing some useful redundancy and allowing for alternative selections. Beam tests are carried out at CERN with a prototype calorimeter to determine its calibration with both high energy (20-150 GeV) and low energy electrons (1-10 GeV). In late summer a pilot run is scheduled with up to three tracking stations and the calorimeter integrated within a common triggerless readout system. The main motivations for the MUonE calorimeter are discussed, and the status and first performance results will be presented.

hep-ex↗
arXiv1999

Density profiles of dark matter halos in an improved Secondary Infall model

In this paper we calculate the density profiles of virialized halos both in the case of structure evolving hierarchically from a scale-free Gaussian delta-field having a power spectrum P(k)=A k^n in a Omega=1 Universe and in the case of the CDM model, by using a modified version of Hoffman & Shaham's (1985) (hereafter HS) and Hoffman's (1988) model. We suppose that the initial density contrast profile around local maxima is given by the mean peak profile introduced by Bardeen et al. (1986) (hereafter BBKS), and is not just proportional to the two-point correlation function, as assumed by HS. We show that the density profiles, both for scale-free Universes and the CDM model, are not power-laws but have a logarithmic slope that increases from the inner halo to its outer parts. Both scale-free, for n >=-1, and CDM density profiles are well approximated by Navarro et al. (1995, 1996, 1997) profile. The radius a, at which the slope alpha=-2, is a function of the mass of the halo and in the scale-free models also of the spectral index n.

astro-ph↗
arXiv1999

Kuiper Belt evolution due to dynamical friction

In this paper we study the role of dynamical friction on the evolution of a population of large objects ($m>10^{22}$ g) at heliocentric distances $>70$ AU in the Kuiper Belt. We show that the already flat distribution of these objects must flatten further due to non-spherically symmetric distribution of matter in the Kuiper Belt. Moreover the dynamical drag, produced by dynamical friction, causes objects of masses $\geq 10^{24} g$ to lose angular momentum and to fall through more central regions in a timescale $\approx 10^9 yr$. This mechanism is able to transport inwards objects of the size of Pluto, supposing it was created beyond 50 AU, according to a Stern & Colwell's (1997b) suggestion.

astro-ph↗