Towards a Muon Collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work.Comment: 118 pages, 103 figure

Towards a muon collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work

Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a $Z$ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 $< p_{\textrm{T}} < 100$ GeV and in the pseudorapidity range $2.5 < \eta < 4$. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb$^{-1}$. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

Towards a muon collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work

Erratum: Towards a muon collider

The original online version of this article was revised: The additional reference [139] has been added. Tao Han’s ORICD ID has been incorrectly assigned to Chengcheng Han and Chengcheng Han’s ORCID ID to Tao Han. Yang Ma’s ORCID ID has been incorrectly assigned to Lianliang Ma, and Lianliang Ma’s ORCID ID to Yang Ma. The original article has been corrected

A 2D FPGA-based clustering algorithm for the LHCb silicon pixel detector running at 30 MHz

Starting from the next LHC run, the upgraded LHCb data acquisition system will read and process events at the full LHC collision rate (averaging 30 MHz) by means of a large CPU farm. In order to save the power and flexibility of CPUs for the higher level tasks, an effort is being made to address the lowest-level, more repetitive tasks at the earliest stages of the data acquisition, by means of specialized processors, generally called “accelerators”. Modern FPGA devices are very well-suited to perform with a high degree of parallelism certain computations, that would be significantly time demanding if performed on general-purpose CPUs. This thesis describes a custom firmware implementation of a new 2D cluster-finder algorithm for the LHCb VELO pixel detector, that will run in the LHCb FPGA readout cards in real time during data taking at the unprecedented event rate of 30 MHz. The results and the performances achieved with this specialized system are reported after being measured in tests emulating realistic running conditions of the LHCb Upgrade and the operation of the clustering algorithm at low level

"Estrapolazione e analisi di dati appartenenti ad applicazioni commerciali attraverso strumenti di business intelligence."

L’ obiettivo di questa relazione è quello di descrivere l’attività che ha caratterizzato il mio tirocinio curricolare. Esso si è tenuto presso Apparound, un’azienda con sede a Montacchiello, in provincia di Pisa, la quale opera nel settore informatico offrendo soluzioni digitali a supporto delle vendite. In particolare, Apparound ha sviluppato degli applicativi, sia per il contesto web, sia per quello mobile, che vengono poi utilizzati dalle forze di vendita delle aziende clienti al fine di supportare e migliorare tutto il processo di vendita dei propri prodotti o servizi. Ovviamente, tali applicativi vengono customizzati per ciascun cliente in base alle esigenze. Il mio progetto di tesi riguarda il cliente più importante di Apparound, ovvero Vodafone Italia. In sintesi, la mia attività consisteva nell’acquisizione e nell’analisi di dati, relativi a degli applicativi che Apparound ha sviluppato per Vodafone, al fine di produrre e mantenere costantemente aggiornata della reportistica. Tale reportistica, in parte già esistente precedentemente, ha il compito di evidenziare il valore di alcune metriche, le quali ci forniscano delle indicazioni riguardanti aspetti di carattere commerciale e, in generale, sull’utilizzo di questi applicativi. Il progetto di tirocinio nasce proprio dalla volontà di migliorare tutto il comparto della reportistica di Vodafone, sia in termini di quantità e qualità dei dati a disposizione, attraverso l’implementazione di un data warehouse che conterrà i dati acquisiti, sia attraverso la produzione di nuovi rapporti informativi, i quali mostreranno informazioni non ancora evidenziate. Un altro importante obiettivo che il tirocinio si prefissava era quello di automatizzare l’intero processo di aggiornamento dei dati e, conseguentemente, dei report. Per quanto riguarda le tecnologie utilizzate nel corso del progetto, esso si è svolto in ambito Microsoft, il quale costituisce l’ambiente di riferimento per Apparound. Infatti, il data warehouse è stato sviluppato attraverso Microsoft SQL Server ed è stato popolato, a partire dai dati contenuti nei database degli applicativi Vodafone, attraverso procedure di ETL costruite con Microsoft SQL Server Integration Services. Anche la reportistica è stata prodotta con Power BI, lo strumento di Microsoft dedicato al data reporting. The aim of this report is to describe the activity that characterized my curricular internship. It is held at Apparound, a company based in Montacchiello, in the province of Pisa, which operates in the IT sector and provides digital solutions to support sales. In particular, Apparound has developed applications, both for web and mobile context, which are then used by the sales forces of corporate customers in order to support and improve the entire sales process of their products or services. Obviously, these applications are customized for each customer according to needs. My thesis project concerns Apparound's most important client, namely Vodafone Italia. In summary, my activity consisted in the acquisition and analysis of data, relating to the applications that Apparound developed for Vodafone, in order to produce and keep constantly updated reports. These reports, partly already existing previously, have the task of highlighting the value of some metrics, which provide us with indications regarding commercial aspects and, in general, on the use of these applications. The internship project was born precisely from the desire to improve the entire comparison of Vodafone reporting, both in terms of quantity and quality of the data available, through the implementation of a data warehouse that will contain the acquired data, and through the production of new information reports, which will show information not yet highlighted. Another important goal od the internship set was to automate the entire process of updating the data and, consequently, the reports. About the technologies used during the project, it is carried out within Microsoft, which constitutes the reference environment for Apparound. In fact, the data warehouse was developed using Microsoft SQL Server and was populated, starting from the data contained in the databases of Vodafone applications, through ETL procedures built with Microsoft SQL Server Integration Services. The reporting was also produced with Power BI, Microsoft's tool dedicated to data reporting