arXiv subjects

Anirban Majumdar

Publications and source records attributed to Anirban Majumdar.

25 records · Page 2Linked to original sources

arXiv2023

Implications of first LZ and XENONnT results: A comparative study of neutrino properties and light mediators

Next generation direct dark matter detection experiments are favorable facilities to probe neutrino properties and light mediators beyond the Standard Model. We explore the implications of the recent data reported by LUX-ZEPLIN (LZ) and XENONnT collaborations on electromagnetic neutrino interactions and neutrino generalized interactions (NGIs). We show that XENONnT places the most stringent upper limits on the effective and transition neutrino magnetic moment (of the order of few $\times 10^{-12}~μ_B$) as well as stringent constraints to neutrino millicharge (of the order of $\sim 10^{-13}~e$)--competitive to LZ--and improved by about one order of magnitude in comparison to existing constraints coming from Borexino and TEXONO. We furthermore explore the XENONnT and LZ sensitivities to simplified models with light NGIs and find improved constraints in comparison to those extracted from Borexino-Phase II data.

hep-ph↗

arXiv2022

Physics implications of recent Dresden-II reactor data

Prompted by the recent Dresden-II reactor data we examine its implications for the determination of the weak mixing angle, paying attention to the effect of the quenching function. We also determine the resulting constraints on the unitarity of the neutrino mixing matrix, as well as on the most general type of nonstandard neutral-current neutrino interactions.

hep-ph↗

arXiv2022

Dark matter detectors as a novel probe for light new physics

We explore the prospect of constraining light mediators at the next generation direct detection dark matter detectors through coherent elastic neutrino-nucleus scattering (CE$ν$NS) and elastic neutrino-electron scattering (E$ν$ES) measurements. Taking into account various details like the quenching factor corrections, atomic binding effects, realistic backgrounds, detection efficiency, energy resolution etc., we consider two representative scenarios regarding detector specifications. For both scenarios, we obtain the model-independent projected sensitivities for all possible Lorentz-invariant interactions, namely scalar ($S$), pseudoscalar ($P$), vector ($V$), axial vector ($A$) and tensor ($T$). For the case of vector interactions, we also focus on two concrete examples: the well-known $U(1)_{B-L}$ and $U(1)_{L_μ- L_τ}$ gauge symmetries. For all interaction channels $X=\{S,P,V,A,T\}$, our results imply that the upcoming dark matter detectors have the potential to place competitive constraints, improved by about 1 order of magnitude compared to existing ones from dedicated CE$ν$NS experiments, XENON1T, beam dump experiments and collider probes.

hep-ph↗

arXiv2021

Reconfiguration and Message Losses in Parameterized Broadcast Networks

Broadcast networks allow one to model networks of identical nodes communicating through message broadcasts. Their parameterized verification aims at proving a property holds for any number of nodes, under any communication topology, and on all possible executions. We focus on the coverability problem which dually asks whether there exists an execution that visits a configuration exhibiting some given state of the broadcast protocol. Coverability is known to be undecidable for static networks, i.e. when the number of nodes and communication topology is fixed along executions. In contrast, it is decidable in PTIME when the communication topology may change arbitrarily along executions, that is for reconfigurable networks. Surprisingly, no lower nor upper bounds on the minimal number of nodes, or the minimal length of covering execution in reconfigurable networks, appear in the literature. In this paper we show tight bounds for cutoff and length, which happen to be linear and quadratic, respectively, in the number of states of the protocol. We also introduce an intermediary model with static communication topology and non-deterministic message losses upon sending. We show that the same tight bounds apply to lossy networks, although, reconfigurable executions may be linearly more succinct than lossy executions. Finally, we show NP-completeness for the natural optimisation problem associated with the cutoff.

cs.LO↗

arXiv2020

Synthesizing safe coalition strategies

Concurrent games with a fixed number of agents have been thoroughly studied, with various solution concepts and objectives for the agents. In this paper, we consider concurrent games with an arbitrary number of agents, and study the problem of synthesizing a coalition strategy to achieve a global safety objective. The problem is non-trivial since the agents do not know a priori how many they are when they start the game. We prove that the existence of a safe arbitrary-large coalition strategy for safety objectives is a PSPACE-hard problem that can be decided in exponential space.

cs.LO↗

arXiv2020

Playing with Repetitions in Data Words Using Energy Games

We introduce two-player games which build words over infinite alphabets, and we study the problem of checking the existence of winning strategies. These games are played by two players, who take turns in choosing valuations for variables ranging over an infinite data domain, thus generating multi-attributed data words. The winner of the game is specified by formulas in the Logic of Repeating Values, which can reason about repetitions of data values in infinite data words. We prove that it is undecidable to check if one of the players has a winning strategy, even in very restrictive settings. However, we prove that if one of the players is restricted to choose valuations ranging over the Boolean domain, the games are effectively equivalent to single-sided games on vector addition systems with states (in which one of the players can change control states but cannot change counter values), known to be decidable and effectively equivalent to energy games. Previous works have shown that the satisfiability problem for various variants of the logic of repeating values is equivalent to the reachability and coverability problems in vector addition systems. Our results raise this connection to the level of games, augmenting further the associations between logics on data words and counter systems.

cs.LO↗

arXiv2019

Computing the Width of Non-deterministic Automata

We introduce a measure called width, quantifying the amount of nondeterminism in automata. Width generalises the notion of good-for-games (GFG) automata, that correspond to NFAs of width 1, and where an accepting run can be built on-the-fly on any accepted input. We describe an incremental determinisation construction on NFAs, which can be more efficient than the full powerset determinisation, depending on the width of the input NFA. This construction can be generalised to infinite words, and is particularly well-suited to coBüchi automata. For coBüchi automata, this procedure can be used to compute either a deterministic automaton or a GFG one, and it is algorithmically more efficient in the last case. We show this fact by proving that checking whether a coBüchi automaton is determinisable by pruning is NP-complete. On finite or infinite words, we show that computing the width of an automaton is EXPTIME-complete. This implies EXPTIME-completeness for multipebble simulation games on NFAs.

cs.FL↗