arXiv subjects

Benoit Viaud

Publications and source records attributed to Benoit Viaud.

7 recordsLinked to original sources

arXiv2025

The High Voltage Splitter board for the JUNO SPMT system

The Jiangmen Underground Neutrino Observatory (JUNO) in southern China is designed to study neutrinos from nuclear reactors and natural sources to address fundamental questions in neutrino physics. Achieving its goals requires continuous operation over a 20-year period. The small photomultiplier tube (small PMT or SPMT) system is a subsystem within the experiment composed of 25600 3-inch PMTs and their associated readout electronics. The High Voltage Splitter (HVS) is the first board on the readout chain of the SPMT system and services the PMTs by providing high voltage for biasing and by decoupling the generated physics signal from the high-voltage bias for readout, which is then fed to the front-end board. The necessity to handle high voltage, manage a large channel count, and operate stably for 20 years imposes significant constraints on the physical design of the HVS. This paper serves as a comprehensive documentation of the HVS board: its role in the SPMT readout system, the challenges in its design, performance and reliability metrics, and the methods employed for production and quality control.

physics.ins-det↗

arXiv2023

Multi-Calorimetry in Light-based Neutrino Detectors

Neutrino detectors are among the largest photon detection instruments, built to capture scarce photons upon energy deposition. Many discoveries in neutrino physics, including the neutrino itself, are inseparable from the advances in photon detection technology, particularly in photo-sensors and readout electronics, to yield ever higher precision and richer detection information. The measurement of the energy of neutrinos, referred to as calorimetry, can be achieved in two distinct approaches: photon-counting, where single-photon can be counted digitally, and photon-integration, where multi-photons are aggregated and estimated via analogue signals. The energy is pursued today to reach permille level systematics control precision in ever-vast volumes, exemplified by experiments like JUNO. The unprecedented precision brings to the foreground the systematics due to calorimetric response entanglements in energy, position and time that were negligible in the past, thus driving further innovation in calorimetry. This publication describes a novel articulation that detectors can be endowed with multiple photon detection systems. This multi-calorimetry approach opens the notion of dual-calorimetry detector, consisting of both photon-counting and photon-integration systems, as a cost-effective evolution from the single calorimetry setups used over several decades for most experiments so far. The dual-calorimetry design exploits unique response synergies between photon-counting and photon-integration systems, including correlations and cancellations in calorimetric responses, to maximise the mitigation of response entanglements, thereby yielding permille-level high-precision calorimetry.

hep-ex↗

arXiv2021

Mass production and characterization of 3-inch PMTs for the JUNO experiment

26,000 3-inch photomultiplier tubes (PMTs) have been produced for Jiangmen Underground Neutrino Observatory (JUNO) by the Hainan Zhanchuang Photonics Technology Co., Ltd (HZC) company in China and passed all acceptance tests with only 15 tubes rejected. The mass production began in 2018 and elapsed for about 2 years at a rate of $\sim$1,000~PMTs per month. The characterization of the PMTs was performed in the factory concurrently with production as a joint effort between HZC and JUNO. Fifteen performance parameters were tracked at different sampling rates, and novel working strategies were implemented to improve quality assurance. This constitutes the largest sample of 3-inch PMTs ever produced and studied in detail to date.

physics.ins-det↗

arXiv2020

Synergies and Prospects for Early Resolution of the Neutrino Mass Ordering

The measurement of neutrino Mass Ordering (MO) is a fundamental element for the understanding of leptonic flavour sector of the Standard Model of Particle Physics. Its determination relies on the precise measurement of $\Delta m^2_{31}$ and $\Delta m^2_{32}$ using either neutrino vacuum oscillations, such as the ones studied by medium baseline reactor experiments, or matter effect modified oscillations such as those manifesting in long-baseline neutrino beams (LB$\nu$B) or atmospheric neutrino experiments. Despite existing MO indication today, a fully resolved MO measurement ($\geq$5$\sigma$) is most likely to await for the next generation of neutrino experiments: JUNO, whose stand-alone sensitivity is $\sim$3$\sigma$, or LB$\nu$B experiments (DUNE and Hyper-Kamiokande). Upcoming atmospheric neutrino experiments are also expected to provide precious information. In this work, we study the possible context for the earliest full MO resolution. A firm resolution is possible even before 2028, exploiting mainly vacuum oscillation, upon the combination of JUNO and the current generation of LB$\nu$B experiments (NOvA and T2K). This opportunity is possible thanks to a powerful synergy boosting the overall sensitivity where the sub-percent precision of $\Delta m^2_{32}$ by LB$\nu$B experiments is found to be the leading order term for the MO earliest discovery. We also found that the comparison between matter and vacuum driven oscillation results enables unique discovery potential for physics beyond the Standard Model.

hep-ph↗

arXiv2016

Novel approach to measure the leptonic eta(')->mu+mu- decays via charmed meson decays

In this article, we propose a novel approach to measure the branching ratios of the leptonic eta(')-> mu+mu- decays by using charmed meson decays, namely, D+(s)->pi+ eta(')(->mu+mu-) and D0->K-pi+eta(')(->mu+mu-). We advocate that the data available at LHCb can already yield a new measurement of Br(eta->mu+mu-) with accuracy competitive with the current world average. We also estimate that using the data collected by LHCb between 2015 and 2018 in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.0/fb, the relative uncertainties to this branching ratio can be reduced down to ~10%. We also show that the first observation of Br(eta'->mu+mu-) may be possible with the Upgrade of the LHCb experiment.

hep-ph↗

arXiv2016

On the potential of multivariate techniques for the determination of multidimensional efficiencies

Differential measurements of particle collisions or decays can provide stringent constraints on physics beyond the Standard Model of particle physics. In particular, the distributions of the kinematical and angular variables that characterise heavy me- son multibody decays are non trivial and can sign the underlying interaction physics. In the era of high luminosity opened by the advent of the Large Hadron Collider and of Flavor Factories, differential measurements are less and less dominated by statistical precision and require a precise determination of efficiencies that depend simultaneously on several variables and do not factorise in these variables. This docu- ment is a reflection on the potential of multivariate techniques for the determination of such multidimensional efficiencies. We carried out two case studies that show that multilayer perceptron neural networks can determine and correct for the distortions introduced by reconstruction and selection criteria in the multidimensional phase space of the decays $B^{0}\rightarrow K^{*0}(\rightarrow K^{+}\pi^{-}) \mu^{+}\mu^{-}$ and $D^{0}\rightarrow K^{-}\pi^{+}\pi^{+}\pi^{-}$, at the price of a minimal analysis effort. We conclude that this method can already be used for measurements which statistical precision does not yet reach the percent level and that with more sophisticated machine learning methods, the aforementioned potential is very promising.

physics.data-an↗

arXiv2012

Investigating charmonium production at LHC with the p pbar final state

We propose to investigate various charmonium states using their common decay channel to p pbar at LHC. Having the branching ratios for charmonium decaying into the p pbar final state measured or calculated, we propose to measure the charmonium production rate for both hadroproduction including soft-diffraction and inclusive production from b-hadron decays. We discuss the theoretical impacts in QCD of measuring different charmonium production rates and also the experimental prospects at LHCb, in particular, those for yet unmeasured eta_c and h_c.

hep-ph↗