New experimental limits on violations of the Pauli exclusion principle obtained with the Borexino Counting Test Facility

EPJ logo New experimental limits on violations of the Pauli exclusion principle obtained with the Borexino Counting Test Facility
The European Physical Journal C – Particles and Fields volume 37, pages 421–431 (2004)
Published: November 2004
doi:10.1140/epjc/s2004-01991-1 (local copy)

Abstract

The Pauli exclusion principle (PEP) has been tested for nucleons (n,p) in ¹²C and ¹⁶O nuclei, using the results of background measurements with the prototype of the Borexino detector, the Counting Test Facility (CTF). The approach consisted of a search for γ, n, p and/or α’s emitted in a non-Paulian transition of 1P-shell nucleons to the filled 1S_1/2 shell in nuclei. Similarly, the Pauli-forbidden β^± decay processes were searched for. Due to the extremely low background and the large mass (4.2 tons) of the CTF detector, the following most stringent up-to-date experimental bounds on PEP violating transitions of nucleons have been established:
$\tau(^{12}C\rightarrow^{12}\tilde{C}+\gamma)>2.1\times10^{27}$ $yr$ ,
$\tau(^{12}C\rightarrow^{11}\tilde{B}+p)>5.0\times10^{26}$ $yr$ ,
$\tau(^{12}C(^{16}O)\rightarrow^{11}\tilde{C}(^{15}\tilde{O})+n)>3.7\times10^{26}$ $yr$ ,
$\tau(^{12}C\rightarrow^{8}\tilde{Be}+\alpha)>6.1\times10^{23}$ $yr$ ,
$\tau(^{12}C\rightarrow^{12}\tilde{N}+e^{-}+\tilde{\nu}_{e})>7.6\times10^{27}$ $yr$ ,
$\tau(^{12}C\rightarrow^{12}\tilde{B}+e^{+}+\nu_{e})>7.7\times10^{27}$ $yr$ ,
all at 90 % C.L.