Heavy Neutral Lepton MASS LIMITS INSPIRE search

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:
ACHARD 2001B
PL B517 75 Search for Heavy Neutral and Charged Leptons in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Annihilation at LEP
ABBIENDI 2000I
EPJ C14 73 Search for Unstable Heavy and Excited Leptons at LEP-2
ABREU 1999O
EPJ C8 41 Search for Composite and Exotic Fermions at LEP-2
BUSKULIC 1996S
PL B384 439 Search for Heavy Lepton Pair Production in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at the Centre-of-Mass Energies of 130 and 136 GeV