Limits for Excited ${{\mathit \tau}}$ (${{\mathit \tau}^{*}}$) from Pair Production

INSPIRE   JSON  (beta) PDGID:
S054TXP
Except for CHEKHOVSKY 2025E, these limits are obtained from ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \tau}^{*+}}{{\mathit \tau}^{*-}}$ and thus rely only on the (electroweak) charge of ${{\mathit \tau}^{*}}$. Form factor effects are ignored unless noted. For the case of limits from ${{\mathit Z}}$ decay, the ${{\mathit \tau}^{*}}$ coupling is assumed to be of sequential type. All limits assume a dominant ${{\mathit \tau}^{*}}$ $\rightarrow$ ${{\mathit \tau}}{{\mathit \gamma}}$ decay except the limits from $\Gamma\mathrm {({{\mathit Z}})}$. For limits prior to 1987, see our PDG 1992 edition (Physical Review D45 S1 (1992)).
S054TXP
VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$\bf{>103.2}$ 95 1
ABBIENDI
2002G
 
OPAL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \tau}^{*}}{{\mathit \tau}^{*}}$ Homodoublet type
• • We do not use the following data for averages, fits, limits, etc. • •
2
CHEKHOVSKY
2025E
 
CMS ${{\mathit \tau}^{\,'}}$ $\rightarrow$ ${{\mathit \tau}}{{\mathit a}_{{{\tau}}}}$, ${{\mathit a}_{{{\tau}}}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
$>102.8$ 95 3
ACHARD
2003B
 
L3 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \tau}^{*}}{{\mathit \tau}^{*}}$ Homodoublet type
1  From ${{\mathit e}^{+}}{{\mathit e}^{-}}$ collisions at $\sqrt {\mathit s }$ = $183 - 209$ GeV. ${{\mathit f}}$ = ${{\mathit f}^{\,'}}$ is assumed.
2  CHEKHOVSKY 2025E search for pair production of vector-like ${{\mathit \tau}^{\,'}}$ in collisions at $\sqrt {s }$ = 13 TeV. ${{\mathit \tau}^{\,'}}$ is assumed to be an SU(2)$_{W}$ singlet decaying to ${{\mathit \tau}}$ and light pseudoscalar ${{\mathit a}_{{{\tau}}}}$ decaying to ${{\mathit \gamma}}{{\mathit \gamma}}$. See their Fig. 5 for limits on $\sigma $.
3  From ${{\mathit e}^{+}}{{\mathit e}^{-}}$ collisions at $\sqrt {\mathit s }$ = $189 - 209$ GeV. ${{\mathit f}}$ = ${{\mathit f}^{\,'}}$ is assumed. ACHARD 2003B also obtain limit for ${{\mathit f}}$ = $−{{\mathit f}^{\,'}}$: ${\mathit m}_{{{\mathit \tau}^{*}}}>96.6$ GeV.
References