Undercoverage in high-statistics counting experiments with finite MC samples

We consider the problem of setting a confidence interval on a parameter of interest from a high-statistics counting experiment in the presence of systematic uncertainties modeled as unconstrained nuisance parameters. We use the profile-likelihood test statistic in the asymptotic limit for confidence interval setting and focus on the case where the likelihood function is derived from a finite sample of Monte Carlo simulated events. We prove as a general result that statistical uncertainties in the Monte Carlo sample affect the coverage of the confidence interval always in the same direction, namely they lead to a systematic undercoverage of the interval. We argue that such spurious effects might not be fully accounted for by statistical methods that are usually adopted in HEP measurements to counteract the effects of finite-size MC samples, such as those based on the Barlow-Beeston likelihood

Correlated-photon imaging at 10 volumetric images per second

The correlation properties of light provide an outstanding tool to overcome the limitations of traditional imaging techniques. A relevant case is represented by correlation plenoptic imaging (CPI), a quantum-inspired volumetric imaging protocol employing spatio-temporally correlated photons from either entangled or chaotic sources to address the main limitations of conventional light-field imaging, namely, the poor spatial resolution and the reduced change of perspective for 3D imaging. However, the application potential of high-resolution imaging modalities relying on photon correlations is limited, in practice, by the need to collect a large number of frames. This creates a gap, unacceptable for many relevant tasks, between the time performance of correlated-light imaging and that of traditional imaging methods. In this article, we address this issue by exploiting the photon number correlations intrinsic in chaotic light, combined with a cutting-edge ultrafast sensor made of a large array of single-photon avalanche diodes (SPADs). This combination of source and sensor is embedded within a novel single-lens CPI scheme enabling to acquire 10 volumetric images per second. Our results place correlated-photon imaging at a competitive edge and prove its potential in practical applications.Comment: 13 pages, 6 figure

Demonstration of particle tracking with scintillating fibres read out by a SPAD array sensor and application as a neutrino active target

Scintillating fibre detectors combine sub-mm resolution particle tracking, precise measurements of the particle stopping power and sub-ns time resolution. Typically, fibres are read out with silicon photomultipliers (SiPM). Hence, if fibres with a few hundred mm diameter are used, either they are grouped together and coupled with a single SiPM, losing spatial resolution, or a very large number of electronic channels is required. In this article we propose and provide a first demonstration of a novel configuration which allows each individual scintillating fibre to be read out regardless of the size of its diameter, by imaging them with Single-Photon Avalanche Diode (SPAD) array sensors. Differently from SiPMs, SPAD array sensors provide single-photon detection with single-pixel spatial resolution. In addition, O(us) or faster coincidence of detected photons allows to obtain noise-free images. Such a concept can be particularly advantageous if adopted as a neutrino active target, where scintillating fibres alternated along orthogonal directions can provide isotropic, high-resolution tracking in a dense material and reconstruct the kinematics of low-momentum protons (down to 150 MeV/c), crucial for an accurate characterisation of the neutrino nucleus cross section. In this work the tracking capabilities of a bundle of scintillating fibres coupled to SwissSPAD2 is demonstrated. The impact of such detector configuration in GeV-neutrino experiments is studied with simulations and reported. Finally, future plans, including the development of a new SPAD array sensor optimised for neutrino detection, are discussed

Compartmental tongue surgery for intermediate-advanced squamous cell carcinoma: A multicentric study

Background: A multicentric study was conducted on technical reproducibility of compartmental tongue surgery (CTS) in advanced tongue cancers (OTSCC) and comparison to standard wide margin surgery (SWMS). Methods: We studied 551 patients with OTSCC treated by CTS and 50 by SWMS. Oncological outcomes were analyzed. A propensity score was performed to compare survival endpoints for the two cohorts. Results: In the CTS group, survival and prognosis were significantly associated with positive lymph-nodes, extranodal extension, depth of invasion and involvement of the soft tissue connecting the tongue primary tumor to neck lymph nodes (T-N tract), independently from the center performing the surgery. SWMS versus CTS showed a HR Cause-Specific Survival (CSS) of 3.24 (95% CI: 1.71-6.11; p < 0.001); HR Loco-Regional Recurrence Free Survival (LRRFS) of 2.54 (95% CI: 1.47-4.40; p < 0.001); HR Overall Survival (OS) of 0.11 (95% CI: 0.01-0.77; p = 0.03). Conclusion: Performing the CTS could provide better CSS and LRRFS than SWMS regardless of the center performing the surgery, in advanced OTSSC

Production of photons from electroweak vector boson fusion in sqrt(s) = 13 TeV proton-proton collisions with the CMS experiment at CERN

The object of this Master's thesis is the measurement of the Electroweak production of photons in association with two jets from proton collisions, with data collected by the CMS experiment at CERN during the ”Run II”. These events are important to test the SU(2)_LxU(1)_Y symmetry of the Electroweak interactions, in particular the self-couplings between the Gauge bosons resulting from the aforementioned symmetry. At the center-of-mass energy of 13 TeV reached at the LHC, the Electroweak production of the photon and the jets also involve Electroweak diagrams in which the photon is produced by the fusion of the massive Vector Bosons W radiated from each of the colliding partons, hence this process is more commonly referred to as Vector Boson Fusion, in particular Vector Boson Fusion to $\gamma$. The cross-section calculated including only the Vector Boson Fusion diagram diverges at high energies resulting in the violation of unitarity. The presence of other Electroweak same final state diagrams which interfere destructively prevents the cross-section from growing indefinitely. This Gauge cancellation mechanism must therefore be extremely precise for it to work, as even slight deviations from the Standard Model predictions would result in the divergence of the cross-section, thus hinting at the presence of new Physics which keeps the cross-section finite at high energies. Therefore this measurement, and more in general Vector Boson Fusion ones, allows to set stringent limits on Physics Beyond the Standard Model, often modelled as Anomalous Gauge Couplings. To measure this process, events with a photon of p_T>220 GeV and two jets with m_{jj}>200 GeV are selected. For signal events, these jets are usually reconstructed using only the information on the electromagnetic and hadronic calorimeters, as they are often outside the acceptance of the tracking system. The photon is instead within the tracker acceptance. This thesis starts with the description of the Standard Model with particular attention to SU(2)_LxU(1)_Y and its Gauge boson self-couplings (chapter 1). The Compact Muon Solenoid experiment at the Large Hadron Collider at CERN is presented in chapter 2. The thesis work started from studies of the main features of the signal using Monte-Carlo simulations only including the Matrix Element calculations (chapter 3), and then moved to study the selection of the correct jets out of all those present in the events, using full Monte-Carlo simulations (chapter 4). Another important feature of Vector Boson Fusion events is the presence of a "rapidity gap" between the jets in which little additional hadronic activity is present. As already said, the jets are mostly outside of the tracking system acceptance, and the only central object is the photon, so few tracks are expected for these events. Because of this, the correct choice of the main Primary Vertex is studied, in particular the fraction of times in which the vertex is chosen correctly. Then characteristics of the vertices chosen correctly and incorrectly are studied, to better understand the causes for the wrong vertex choice. Then the impact of the vertex choice on the invariant mass is studied. This is described in chapter 5. The analysis to measure Electroweak $\gamma+2$ jets is presented in chapter 6. The main background to this analysis is the mixed QCD/EW production of photon in association with jets. This is simulated using full Monte-Carlo simulation, whose predictions are validated by a Control Region with Z->l+ l- events and two jets with the same kinematic cuts. Another important source of background events is the pure QCD production of multijet events in which an object is mistakenly reconstructed as a single isolated photon, this objects are usually $\pi_0$s produced in jets. This source is instead validated using a data-driven approach using the $\sigma_{i\eta i\eta}$ and photon isolation variables. The analysis is performed first in the Control Region and a fit to measure the Electroweak Z-> l+l-+2 jets is performed on the output of a Boosted Decision Tree specifically built to discriminate Electroweak $\gamma+2$ jets events and its main background. This was done for all three years. Then this is repeated on the Signal Region for 2016 and the expected total uncertainty and significance were extracted. Both in Z+2 jets Control Region and the $\gamma+2$ jets Signal Region various sources of systematic uncertainties, Jet Energy Scale and Resolution and the variation of the QCD $\mu_R$ and $\mu_F$ scales. Finally chapter 7 summarizes the results of the various chapters of this thesis and also discusses future directions for this work

Pupil Data Upon Stimulation by Auditory Stimuli

Evaluating hearing in newborns and uncooperative patients can pose a considerable challenge. One potential solution might be to employ the Pupil Dilation Response (PDR) as an objective physiological metric. In this dataset descriptor paper, we present a collection of data showing changes in pupil dimension and shape upon presentation of auditory stimuli. In particular, we collected pupil data from 16 subjects, with no known hearing loss, upon different lighting conditions, measured in response to a series of 60-100 audible tones, all of the same frequency and amplitude, which may serve to further investigate any relationship between hearing capabilities and PDRs. Dataset: Data is available at https://zenodo.org/doi/10.5281/zenodo.10497437. Dataset License: CC-BY-4.