S. Martellotti
A5023583092- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Particle Detector Development and Performance
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Cosmology and Gravitation Theories
- Medical Imaging Techniques and Applications
- Black Holes and Theoretical Physics
- Advanced Data Storage Technologies
- Nuclear physics research studies
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Laser-induced spectroscopy and plasma
- Stochastic processes and statistical mechanics
- Magnetic confinement fusion research
- Astrophysics and Cosmic Phenomena
- Muon and positron interactions and applications
- Distributed and Parallel Computing Systems
- Advanced X-ray Imaging Techniques
- Radiation Effects in Electronics
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2015-2024
Roma Tre University
2024
Charles University
2023-2024
UCLouvain
2022-2023
Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
2022
University of Ferrara
2022
University of Brescia
2022
Budker Institute of Nuclear Physics
2014-2020
University of California, Irvine
2020
Istituto Nazionale di Fisica Nucleare, Sezione di Bologna
2020
Based on the full BaBar data sample, we report improved measurements of ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B l Nu), where is either e or mu. These are sensitive to new physics contributions in form a charged Higgs boson. We measure R(D) 0.440 +- 0.058 0.042 and R(D*) 0.332 0.024 0.018, which exceed Standard Model expectations by 2.0 sigma 2.7 sigma, respectively. Taken together, our results disagree with these at 3.4 level. This excess cannot be explained boson type II two-Higgs-doublet...
Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce light mediator, so-called photon (A′), connecting sector to standard model. We present search for reaction e+e−→γA′, A′→e+e−, μ+μ− using 514 fb−1 data collected with BABAR detector. observe no statistically significant deviations from model predictions, and we set 90% confidence level upper limits on mixing strength between at 10−4−10−3...
We search for single-photon events in 53 fb−1 of e+e− collision data collected with the BABAR detector at PEP-II B-Factory. look a single high-energy photon and large missing momentum energy, consistent production spin-1 particle A′ through process e+e−→γA′; A′→invisible. Such particles, referred to as "dark photons," are motivated by theories applying U(1) gauge symmetry dark matter. find no evidence such processes set 90% confidence level upper limits on coupling strength mass range mA′≤8...
NA62 is a fixed-target experiment at the CERN SPS dedicated to measurements of rare kaon decays. Such measurements, like branching fraction K+ → π+ ν decay, have potential bring significant insights into new physics processes when comparison made with precise theoretical predictions. For this purpose, innovative techniques been developed, in particular, domain low-mass tracking devices. Detector construction spanned several years from 2009 2014. The collaboration started detector...
Many models of physics beyond the Standard Model predict existence new Abelian forces with gauge bosons mediating interactions between "dark sectors" and Model. We report a search for dark boson Z' coupling only to second third generations leptons in reaction e+e- -> mu+mu- Z', using 514 fb-1 data collected by BABAR experiment. No significant signal is observed masses range 0.212 - 10 GeV. Limits on parameter g' as low 7x10^-4 are derived, leading improvements bounds compared those...
A bstract The NA62 experiment reports the branching ratio measurement $$ \mathrm{BR}\left({K}^{+}\to {\pi}^{+}\nu \overline{\nu}\right)=\left({10.6}_{-3.4}^{+4.0}\left|{}_{\mathrm{stat}}\right.\pm {0.9}_{\mathrm{syst}}\right)\times {10}^{-11} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>BR</mml:mi> <mml:mfenced> <mml:mrow> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:mi>π</mml:mi> <mml:mi>ν</mml:mi> <mml:mover> <mml:mo>¯</mml:mo>...
We search for the flavor-changing neutral-current decays $B\ensuremath{\rightarrow}{K}^{(*)}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, and invisible $J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ via $B\ensuremath{\rightarrow}{K}^{(*)}J/\ensuremath{\psi}$ $B\ensuremath{\rightarrow}{K}^{(*)}\ensuremath{\psi}(2S)$, respectively, using a data sample of...
We present a measurement of the total branching fraction flavor-changing neutral-current process B->Xsl+l-, along with partial fractions in bins dilepton and hadronic system (Xs) mass, using sample 471x10^6 Upsilon(4S)->BBbar events recorded BaBar detector at PEP-II e+e- collider. B mesons are reconstructed by combining pair, either or mu+mu-, 10 different Xs final states containing exactly one charged neutral kaon, two fewer pions, most pi0. Using sum over these exclusive modes as basis for...
We present measurements of Collins asymmetries in the inclusive process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}X$, where $\ensuremath{\pi}$ stands for charged pions, at a center-of-mass energy 10.6 GeV. use data sample $468\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected by BABAR experiment PEP-II $B$ factory SLAC, and consider pairs pions produced opposite hemispheres hadronic events. observe clear distributions azimuthal angles two...
A search for heavy neutral lepton production in $K^+$ decays using a data sample collected with minimum bias trigger by the NA62 experiment at CERN 2015 is reported. Upper limits $10^{-7}$ to $10^{-6}$ level are established on elements of extended neutrino mixing matrix $|U_{\ell 4}|^2$ ($\ell=e,\mu$) mass range $170-448~{\rm MeV}/c^2$. This improves results from previous searches decays, setting more stringent and extending range.
A search for heavy neutral lepton (N) production in K+→e+N decays using the data sample collected by NA62 experiment at CERN 2017–2018 is reported. Upper limits of extended neutrino mixing matrix element |Ue4|2 are established level 10−9 over most accessible mass range 144–462 MeV/c2, with assumption that lifetime exceeds 50 ns. These improve significantly upon those previous and decay searches. The favoured Big Bang Nucleosynthesis excluded up to a about 340 MeV/c2.
The NA62 experiment at CERN reports searches for $K^+\to\mu^+N$ and $K^+\to\mu^+\nu X$ decays, where $N$ $X$ are massive invisible particles, using the 2016-2018 data set. particle is assumed to be a heavy neutral lepton, results expressed as upper limits of ${\cal O}(10^{-8})$ neutrino mixing parameter $|U_{\mu4}|^2$ masses in range 200-384 MeV/$c^2$ lifetime exceeding 50 ns. considered scalar or vector hidden sector mediator decaying an final state, decay branching fraction 10-370 reported...
A precise measurement of the cross section for process e+e−→K+K−(γ) from threshold to an energy 5 GeV is obtained with initial-state radiation (ISR) method using 232 fb−1 data collected BABAR detector at e+e− center-of-mass energies near 10.6 GeV. The uses effective ISR luminosity determined e+e−→μ+μ−(γ)γISR same set. corresponding lowest-order contribution hadronic vacuum polarization term in muon magnetic anomaly found be aμKK,LO=(22.93±0.18stat±0.22syst)×10−10. charged kaon form factor...
The ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}p\overline{p}$ cross section and the proton magnetic form factor have been measured in center-of-mass energy range from 3.0 to 6.5 GeV using initial-state radiation technique with an undetected photon. This is first measurement of at energies higher than 4.5 GeV. analysis based on $469\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ integrated luminosity collected BABAR detector PEP-II collider ${e}^{+}{e}^{\ensuremath{-}}$ near 10.6...
Inclusive production cross sections of $\pi^\pm$, $K^\pm$ and $p\bar{p}$ per hadronic $e^+e^-$ annihilation event in are measured at a center-of-mass energy 10.54 GeV, using relatively small sample very high quality data from the BaBar experiment PEP-II $B$-factory SLAC National Accelerator Laboratory. The drift chamber Cherenkov detector provide clean samples identified over wide range momenta. Since is below threshold to produce $B\bar{B}$ pair, with $B$ bottom-quark meson, these represent...
The NA62 experiment at the CERN SPS reports first search for $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ using decay-in-flight technique, based on a sample of $1.21\times10^{11}$ $K^+$ decays collected in 2016. single event sensitivity is $3.15\times 10^{-10}$, corresponding to 0.267 Standard Model events. One signal candidate observed while expected background 0.152 This leads an upper limit $14 \times 10^{-10}$ branching ratio 95\% CL.
The results of a search for $\pi^0$ decays to photon and an invisible massive dark at the NA62 experiment CERN SPS are reported. From total $4.12\times10^8$ tagged mesons, no signal is observed. Assuming kinetic-mixing interaction, limits set on coupling ordinary as function mass, improving previous searches in mass range 60--110 MeV/$c^2$. present interpreted terms upper limit branching ratio electro-weak decay $\pi^0 \to \gamma \nu \overline{\nu}$, current by more than three orders magnitude.
We search for the rare flavor-changing neutral current process $B^{+}\rightarrow K^{+}τ^{+}τ^{-}$ using data from BABAR experiment. The sample, collected at center-of-mass energy of $Υ{(4S)}$ resonance, corresponds to a total integrated luminosity 424 fb$^{-1}$ and 471 million $B\overline{B}$ pairs. reconstruct one $B$ meson, produced in $Υ{(4S)}\rightarrow B^{+} B^{-}$ decay, many hadronic decay modes activity compatible with K^{+} τ^{+}τ^{-}$ rest event. Each $τ$ lepton is required...
We study the lepton forward-backward asymmetry ${\mathcal{A}}_{FB}$ and longitudinal ${K}^{*}$ polarization ${F}_{L}$, as well an observable ${P}_{2}$ derived from them, in rare decays $B\ensuremath{\rightarrow}{K}^{*}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$, where ${\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ is either ${e}^{+}{e}^{\ensuremath{-}}$ or ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, using full sample of 471 million...
A bstract The NA62 experiment at the CERN SPS reports a study of sample 4 × 10 9 tagged π 0 mesons from K + → ( γ ), searching for decay to invisible particles. No signal is observed in excess expected background fluctuations. An upper limit . − set on branching ratio 90% confidence level, improving previous results by factor 60. This result can also be interpreted as model- independent X , where particle escaping detection with mass range 0.110–0.155 GeV /c 2 and rest lifetime greater than...
A sample of 3984 candidates the K+→π+γγ decay, with an estimated background 291±14 events, was collected by NA62 experiment at CERN during 2017–2018. In order to describe observed di-photon mass spectrum, next-to-leading contribution in chiral perturbation theory found be necessary. The decay branching ratio full kinematic range is measured (9.61±0.17)×10−7. first search for production and prompt axion-like particle gluon coupling process K+→π+a, a→γγ also reported.
The design of next-generation calorimeters for accelerator-borne experiments at the intensity frontier poses unprecedented challenges with regard to timing performance and radiation resistance, while rivaling current state art in terms energy resolution. A significant role may be played by quantum dots, i.e., light-emitting semiconductor nanocrystals high yield rather easy manufacture. Quantum dots can cast into an optically transparent polymer matrix obtain nanocomposite scintillators,...
We study the processes $e^+ e^-\to K_S^0 K_L^0 \gamma$, $K_S^0 \pi^+\pi^-\gamma$, and K^+K^-\gamma$, where photon is radiated from initial state, providing cross section measurements for hadronic states over a continuum of center-of-mass energies. The results are based on 469 fb$^{-1}$ data collected with BaBar detector at SLAC. observe $\phi(1020)$ resonance in K_L^0$ final state measure product its electronic width branching fraction about 3% uncertainty. present measurement $ energy range...