In this paper we report on the results of two analyses of the data taken with a dedicated VIP-Lead experiment at the Gran Sasso National Laboratory of the INFN. We use measurements taken in an environment that is especially well screened from cosmic rays, with a metal target made of “Roman lead” which is characterised by a low level of intrinsic radioactivity. The analyses lead to an improvement, on the upper bounds of the Pauli Exclusion Principle violation for electrons, which is more than one (four) orders of magnitude, when the electron-atom interactions are described in terms of scatterings (or close encounters) respectively.

Italy

Kristian Piscicchia

Edoardo Milotti

Aidin Amirkhani

Sergio Bartalucci

Sergio Bertolucci

Massimiliano Bazzi

Romania

Mario Bragadireanu

Austria

Michael Cargnelli

Alberto Clozza

Raffaele Grande

Luca De Paolis

Switzerland

Jean-Pierre Egger

Carlo Fiorini

Carlo Guaraldo

Mihail Iliescu

Matthias Laubenstein

Johann Marton

Marco Miliucci

Andreas Pichler

Dorel Pietreanu

Alessandro Scordo

Hexi Shi

Diana Sirghi

Florin Sirghi

Laura Sperandio

Germany

Oton Vazquez Doce

Johann Zmeskal

Catalina Curceanu

Search for a remnant violation of the Pauli exclusion principle in a Roman lead target

Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several experimental efforts are striving to reach this goal, and the sequence of results promises a success in the next few years. This measurement generally is accompanied by the search for hypothetical light particles that couple to two photons. The PVLAS experiment employs a sensitive polarimeter based on a high finesse Fabry–Perot cavity. In this paper we report on the latest experimental results of this experiment. The data are analysed taking into account the intrinsic birefringence of the dielectric mirrors of the cavity. Besides a new limit on the vacuum magnetic birefringence, the measurements also allow the model-independent exclusion of new regions in the parameter space of axion-like and milli-charged particles. In particular, these last limits hold also for all types of neutrinos, resulting in a laboratory limit on their charge.

Federico Della Valle

Aldo Ejlli

Ugo Gastaldi

Giuseppe Messineo

Ruggero Pengo

Giuseppe Ruoso

Guido Zavattini

The PVLAS experiment: measuring vacuum magnetic birefringence and dichroism with a birefringent Fabry–Perot cavity