Heavy Neutral Lepton MASS LIMITS

INSPIRE   JSON  (beta) PDGID:
S077MN
Limits apply only to heavy lepton type given in comment at right of data Listings.

See the “Quark and Lepton Compositeness, Searches for” Listings for limits on radiatively decaying excited neutral leptons, $\mathit i.e.$ ${{\mathit \nu}^{*}}$ $\rightarrow$ ${{\mathit \nu}}{{\mathit \gamma}}$.

VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$\bf{>101.3}$ 95
ACHARD
2001B
 
L3 Dirac coupling to ${{\mathit e}}$
$\bf{>101.5}$ 95
ACHARD
2001B
 
L3 Dirac coupling to ${{\mathit \mu}}$
$\bf{>90.3}$ 95
ACHARD
2001B
 
L3 Dirac coupling to ${{\mathit \tau}}$
$\bf{>89.5}$ 95
ACHARD
2001B
 
L3 Majorana coupling to ${{\mathit e}}$
$\bf{>90.7}$ 95
ACHARD
2001B
 
L3 Majorana coupling to ${{\mathit \mu}}$
$\bf{>80.5}$ 95
ACHARD
2001B
 
L3 Majorana coupling to ${{\mathit \tau}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$>76.0$ 95
ABBIENDI
2000I
 
OPAL Majorana, coupling to ${{\mathit e}}$
$>88.0$ 95
ABBIENDI
2000I
 
OPAL Dirac, coupling to ${{\mathit e}}$
$>76.0$ 95
ABBIENDI
2000I
 
OPAL Majorana, coupling to ${{\mathit \mu}}$
$>88.1$ 95
ABBIENDI
2000I
 
OPAL Dirac, coupling to ${{\mathit \mu}}$
$>53.8$ 95
ABBIENDI
2000I
 
OPAL Majorana, coupling to ${{\mathit \tau}}$
$>71.1$ 95
ABBIENDI
2000I
 
OPAL Dirac, coupling to ${{\mathit \tau}}$
$>76.5$ 95
ABREU
1999O
 
DLPH Dirac coupling to ${{\mathit e}}$
$>79.5$ 95
ABREU
1999O
 
DLPH Dirac coupling to ${{\mathit \mu}}$
$>60.5$ 95
ABREU
1999O
 
DLPH Dirac coupling to ${{\mathit \tau}}$
$>63$ 95 1, 2
BUSKULIC
1996S
 
ALEP Dirac
$>54.3$ 95 1, 3
BUSKULIC
1996S
 
ALEP Majorana
1  BUSKULIC 1996S requires the decay length of the heavy lepton to be $<1~$cm, limiting the square of the mixing angle $\vert \mathit U_{{{\mathit \ell}} {{\mathit j}}}\vert ^2$ to $10^{-10}$.
2  BUSKULIC 1996S limit for mixing with ${{\mathit \tau}}$. Mass is $>63.6$ GeV for mixing with ${{\mathit e}}$ or ${{\mathit \mu}}$.
3  BUSKULIC 1996S limit for mixing with ${{\mathit \tau}}$. Mass is $>55.2$ GeV for mixing with ${{\mathit e}}$ or ${{\mathit \mu}}$.
References