73 research outputs found
RD53 Collaboration and CHIPIX65 Project for the development of an innovative Pixel Front End Chip for HL-LHC
Full text linkMeasurement of the effective B0s→K+K− lifetime
Full text linkA measurement of the effective lifetime is presented using approximately 37 pb−1 of data collected by LHCb during 2010. This quantity can be used to put constraints on contributions from processes beyond the Standard Model in the meson system and is determined by two complementary approaches as
τKK=1.440±0.096 (stat)±0.008 (syst)±0.003 (model) ps
Observation of J/ψ-pair production in pp collisions at √s=7 TeV
Full text linkThe production of J/ψ pairs in proton–proton collisions at a centre-of-mass energy of 7 TeV has been observed using an integrated luminosity of 37.5 pb−1 collected with the LHCb detector. The production cross-section for pairs with both J/ψ in the rapidity range 2 < yJ/ψ < 4.5 and transverse momentum pJ/ψ T <10 GeV/c is σJ/ψJ/ψ =5.1±1.0±1.1 nb, where the first uncertainty is statistical and the second systematic
Measurement of the Bs0-Bs0 oscillation frequency δms in Bs0→Ds-(3)π decays
Full text linkThe Bs0-Bs0 oscillation frequency δms is measured with 36 pb-1 of data collected in pp collisions at s=7TeV by the LHCb experiment at the Large Hadron Collider. A total of 1381 Bs0→Ds-π+ and Bs0→Ds-π+π-π + signal decays are reconstructed, with average decay time resolutions of 44 fs and 36 fs, respectively. An oscillation signal with a statistical significance of 4.6σ is observed. The measured oscillation frequency is δm s=17.63±0.11(stat)±0.02(syst)ps -1
First observation of the decay Bs0→K*0K*0
Full text linkThe first observation of the decay B0s→K∗0K∗0 is reported using 35 pb−1 of data collected by LHCb in proton–proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8±7.5 B0s→(K+π−)(K−π+) events are observed within ±50 MeV/c2 of the B0s mass and 746 MeV/c2 < mKπ < 1046 MeV/c2, mostly coming from a resonant B0s→K∗0K∗0 signal. The branching fraction and the CP-averaged K∗0 longitudinal polarization fraction are measured to be B(B0s→K∗0K∗0)=(2.81±0.46(stat.)±0.45(syst.)±0.34(fs/ fd))×10−5 and fL =0.31±0.12(stat.)±0.04(syst.)
Measurement of sigma (pp -> bbX) at √s=7 TeV in the forward region
Full text linkDecays of b hadrons into final states containing a D-0 meson and a muon are used to measure the bb; production cross-section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC. In the pseudorapidity interval 2 < eta < 6 and integrated over all transverse momenta we find that the average cross-section to produce b-flavoured or b-flavoured hadrons is (75.3 +/- 5.4 +/- 13.0) mu b
RD53 Collaboration and CHIPIX65 Project for the development of an innovative Pixel Front End Chip for HL-LHC
Full text linkPixel detectors at HL-LHC experiments will be exposed to unprecedented level of radiation and particle flux. This paper describes the program of development of an innovative pixel chip using a CMOS 65nm technology for the first time in HEP community, for experiments with extreme particle rates and radiation at future High Energy Physics colliders. The RD53 collaboration effort is described together with the CHIPIX65 INFN project
Iniezione di posistroni ed elettroni in ALA-6
No full text<p>In questo memorandum riportiamo i risultati ottenuti per l'iniezione nell'anello ALA-6. Sono state prese in considerazione possibili soluzioni per l'iniezione (1)':' a) iniezione diretta da Linac; b) iniezione dal Linac in Adone e successiva estrazione da Adone (mediante un kicker) ed iniezione in ALA. Per l'iniezione direttamente del Linac valgono le considerazioni fatte per l'iniezione in Adone nella ref. 2. Usiamo qui le medesime notazioni. La configurasione dell'ottica usata è riportata nella tab. 1 (3). I conti sono fatti nell'ipotesi di iniettare con i sestupoli accesi.</p>
A 1550 nm laser line to measure light scattering properties for the Einstein Telescope
Full text linkopenLa luce diffusa rappresenta una significativa fonte di rumore nei rivelatori interferometrici di onde gravitazionali, come LIGO, Virgo e il futuro Einstein Telescope. Ridurne la generazione e la ricombinazione con il fascio principale è essenziale per migliorare la sensibilità del rivelatore. Ciò richiede la caratterizzazione delle proprietà di diffusione della luce di materiali, rivestimenti e componenti ottici alla specifica lunghezza d'onda utilizzata.
Mentre LIGO e Virgo utilizzano laser a 1064 nm e 532 nm, l'interferometro a bassa frequenza di Einstein Telescope opererà probabilmente a 1550 nm. Presso il DFA e l'INFN di Padova è già operativo un apparato di misura della diffusione della luce alle lunghezze d'onda impiegate da LIGO e Virgo. Per contribuire alla ricerca relativa ad Einstein Telescope, tale apparato deve essere esteso per consentire misure alla nuova lunghezza d'onda.
In questa tesi si presenta la progettazione, la costruzione e la caratterizzazione di una nuova linea laser a 1550 nm, nonché la sua integrazione nell'apparato esistente. Un sistema di lenti è sviluppato per consentire la regolazione della dimensione del fascio incidente sul campione. La polarizzazione della luce viene sfruttata per variare la potenza del fascio in modo preciso e automatizzato. La modulazione del fascio combinata con l'amplificazione lock-in è impiegata per ridurre il rumore di fondo e migliorare la sensibilità. Infine, l'analisi di un campione di riferimento mostra il comportamento atteso, dimostrando che l'apparato è ora in grado di caratterizzare materiali e rivestimenti di interesse per Einstein Telescope.Stray light is a significant source of noise in laser interferometric gravitational-wave detectors such as LIGO, Virgo, and the upcoming Einstein Telescope. Minimizing its generation and its recoupling with the main beam is essential to improve detector sensitivity. This requires characterization of the light scattering properties of materials, coatings, and optical components at the specific wavelength in use.
While LIGO and Virgo employ lasers at 1064 nm and 532 nm, the low-frequency interferometer of the Einstein Telescope is expected to operate at 1550 nm. At the DFA and INFN of Padova, an experimental facility is already operational for scattering measurements at the LIGO and Virgo wavelengths. To support research relevant to the Einstein Telescope, this facility needs to be extended to include the new wavelength.
This thesis presents the design, implementation, and characterization of a new 1550 nm laser line, as well as its integration into the existing setup. A lens system is developed to enable tunable beam spot sizes on the sample. A precise and automated power control system is implemented using polarization-based techniques. Beam modulation combined with lock-in amplification is employed to suppress background noise and enhance sensitivity. Finally, measurements on a reference sample confirm the expected behavior, demonstrating that the facility is now capable of characterizing materials and coatings relevant to the Einstein Telescope
EuPRAXIA@SPARC_LAB: The high-brightness RF photo-injector layout proposal
No full textAt EuPRAXIA@SPARC_LAB, the unique combination of an advanced high-brightness RF injector and a plasmabased
accelerator will drive a new multi-disciplinary user-facility. The facility, that is currently under study
at INFN-LNF Laboratories (Frascati, Italy) in synergy with the EuPRAXIA collaboration, will operate the
plasma-based accelerator in the external injection configuration. Since in this configuration the stability and
reproducibility of the acceleration process in the plasma stage is strongly influenced by the RF-generated
electron beam, the main challenge for the RF injector design is related to generating and handling high quality
electron beams. In the last decades of R&D activity, the crucial role of high-brightness RF photo-injectors in
the fields of radiation generation and advanced acceleration schemes has been largely established, making them
effective candidates to drive plasma-based accelerators as pilots for user facilities. An RF injector consisting
in a high-brightness S-band photo-injector followed by an advanced X-band linac has been proposed for the
EuPRAXIA@SPARC_LAB project. The electron beam dynamics in the photo-injector has been explored by means
of simulations, resulting in high-brightness, ultra-short bunches with up to 3 kA peak current at the entrance
of the advanced X-band linac booster. The EuPRAXIA@SPARC_LAB high-brightness photo-injector is described
here together with performance optimisation and sensitivity studies aiming to actual check the robustness and
reliability of the desired working point
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