MASS LIMITS for Leptoquarks from Single Production

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These limits depend on the ${{\mathit q}}-{{\mathit \ell}}$-leptoquark coupling $\mathit g_{\mathit LQ}$. It is often assumed that $\mathit g{}^{2}_{\mathit LQ}/4{{\mathit \pi}}$=1/137. Limits shown are for a scalar, weak isoscalar, charge $−$1/3 leptoquark.
VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$>2050$ 95 1
HAYRAPETYAN
2024C
 CMS B(${{\mathit u}}{{\mathit \tau}}$) = 1
$>1800$ 95 2
HAYRAPETYAN
2024C
 CMS B(${{\mathit d}}{{\mathit \tau}}$) = 1
$>780$ 95 3
HAYRAPETYAN
2024Z
 CMS Third generation
$\bf{>1280}$ 95 4
AAD
2023BZ
 ATLS LQ $\rightarrow$ ${{\mathit b}}{{\mathit \tau}}$
$> 550$ 95 5
SIRUNYAN
2021J
 CMS Third generation
$\text{none 150 - 740}$ 95 6
SIRUNYAN
2018BJ
 CMS Third generation
$\bf{>1755}$ 95 7
KHACHATRYAN
2016AG
 CMS First generation
$\bf{>660}$ 95 8
KHACHATRYAN
2016AG
 CMS Second generation
$> 304$ 95 9
ABRAMOWICZ
2012A
 ZEUS First generation
$>73$ 95 10
ABREU
1993J
 DLPH Second generation
• • We do not use the following data for averages, fits, limits, etc. • •
11
AAD
2022E
 ATLS LQ $\rightarrow$ ${{\mathit u}}{{\mathit e}^{-}}$ , ${{\mathit c}}{{\mathit \mu}^{-}}$
12
TUMASYAN
2021D
 CMS First generation
13
DEY
2016
ICCB ${{\mathit \nu}}$ ${{\mathit q}}$ $\rightarrow$ LQ $\rightarrow$ ${{\mathit \nu}}{{\mathit q}}$
14
AARON
2011A
 H1 Lepton-flavor violation
$> 300$ 95 15
AARON
2011B
 H1 First generation
16
ABAZOV
2007E
 D0 Second generation
$> 295$ 95 17
AKTAS
2005B
 H1 First generation
18
CHEKANOV
2005A
 ZEUS Lepton-flavor violation
$>298$ 95 19
CHEKANOV
2003B
 ZEUS First generation
$>197$ 95 20
ABBIENDI
2002B
 OPAL First generation
21
CHEKANOV
2002
ZEUS Repl. by CHEKANOV 2005A
$>290$ 95 22
ADLOFF
2001C
 H1 First generation
$>204$ 95 23
BREITWEG
2001
ZEUS First generation
24
BREITWEG
2000E
 ZEUS First generation
$>161$ 95 25
ABREU
1999G
 DLPH First generation
$>200$ 95 26
ADLOFF
1999
H1 First generation
27
DERRICK
1997
ZEUS Lepton-flavor violation
$>168$ 95 28
DERRICK
1993
ZEUS First generation
1  HAYRAPETYAN 2024C search for single production of scalar leptoquarks decaying to ${{\mathit q}}{{\mathit \tau}^{+}}$ (${{\mathit q}}$ = ${{\mathit u}}$ , ${{\mathit d}}$ , ${{\mathit s}}$ , ${{\mathit b}}$) in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. The limit quoted above is for a leptoquark produced in ${{\mathit \tau}}{{\mathit u}}$ collisions and the leptoquark coupling strength ${{\mathit \lambda}}$ = 1. See their Fig. 4 for limits in mass-coupling plane.
2  HAYRAPETYAN 2024C search for single production of scalar leptoquarks decaying to ${{\mathit q}}{{\mathit \tau}^{+}}$ (${{\mathit q}}$ = ${{\mathit u}}$ , ${{\mathit d}}$ , ${{\mathit s}}$ , ${{\mathit b}}$) in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. The limit quoted above is for a leptoquark produced in ${{\mathit \tau}}{{\mathit d}}$ collisions and the leptoquark coupling strength ${{\mathit \lambda}}$ = 1. See their Fig. 4 for limits in mass-coupling plane.
3  HAYRAPETYAN 2024Z search for scalar and vector leptoquarks decaying to ${{\mathit b}}{{\mathit \tau}}$ and produced through single, pair, and nonresonantly in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. The limit quoted above is derived solely from single production limit and assumes scalar leptoquark decaying to ${{\mathit b}}{{\mathit \tau}}$. The leptoquark coupling strength ${{\mathit \lambda}}$ = 1 is assumed. See their Fig. 7 and Fig. 8 for combined limits in mass-coupling plane.
4  AAD 2023BZ search for single production of charge 4/3 scalar leptoquarks decaying to ${{\mathit b}}{{\mathit \tau}^{-}}$, and charge 2/3 vector leptoquarks decaying to ${{\overline{\mathit b}}}{{\mathit \tau}^{-}}$ in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. The limit quoted above assumes a scalar leptoquark with B(${{\mathit b}}{{\mathit \tau}}$) = 1 and the leptoquark coupling strength ${{\mathit \lambda}}$ = 1.0. The limit becomes ${{\mathit M}_{{{LQ}}}}$ $>$ 1530 GeV for ${{\mathit \lambda}}$ = 2.5.
5  SIRUNYAN 2021J search for single production of charge $−$1/3 scalar leptoquarks decaying to ${{\mathit t}}{{\mathit \tau}^{-}}$ and ${{\mathit b}}{{\mathit \nu}}$, and charge 2/3 vector leptoquarks decaying to ${{\mathit t}}{{\mathit \nu}}$ and ${{\mathit b}}{{\mathit \tau}^{+}}$ in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. The limit quoted above assumes a scalar leptoquark with B(${{\mathit t}}{{\mathit \tau}}$) = B(${{\mathit b}}{{\mathit \nu}}$) = 0.5 and the leptoquark coupling strength ${{\mathit \lambda}}$ = 1.5. The limit becomes ${{\mathit M}_{{{LQ}}}}$ $>$ 750 GeV for ${{\mathit \lambda}}$ = 2.5.
6  SIRUNYAN 2018BJ search for single production of charge 2/3 scalar leptoquarks decaying to ${{\mathit \tau}}{{\mathit b}}$ in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. The limit above assumes B(${{\mathit \tau}}{{\mathit b}}$) = 1 and the leptoquark coupling strength $\lambda $ = 1.
7  KHACHATRYAN 2016AG search for single production of charge $\pm{}$1/3 scalar leptoquarks using ${{\mathit e}}{{\mathit e}}{{\mathit j}}$ events in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV. The limit above assumes B(${{\mathit e}}{{\mathit q}}$) = 1 and the leptoquark coupling strength ${{\mathit \lambda}}$ = 1.
8  KHACHATRYAN 2016AG search for single production of charge $\pm{}$1/3 scalar leptoquarks using ${{\mathit \mu}}{{\mathit \mu}}{{\mathit j}}$ events in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV. The limit above assumes B(${{\mathit \mu}}{{\mathit q}}$) = 1 and the leptoquark coupling strength $\lambda $ = 1.
9  ABRAMOWICZ 2012A limit is for a scalar, weak isoscalar, charge $-1$/3 leptoquark coupled with ${{\mathit e}_{{{R}}}}$. See their Figs. $12 - 17$ and Table 4 for states with different quantum numbers.
10  Limit from single production in ${{\mathit Z}}$ decay. The limit is for a leptoquark coupling of electromagnetic strength and assumes B(${{\mathit \ell}}{{\mathit q}}$) = 2/3. The limit is 77 GeV if first and second leptoquarks are degenerate.
11  AAD 2022E leptoquarks decaying both to ${{\mathit u}}{{\mathit e}^{-}}$ and ${{\mathit c}}{{\mathit \mu}^{-}}$ are constrained from the comparison of the production cross sections for ${{\mathit e}^{+}}{{\mathit \mu}^{-}}$ and ${{\mathit e}^{-}}{{\mathit \mu}^{+}}$ in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. Scalar leptoquarks with $\mathit M_{LQ}$ $<$ 1880 GeV are excluded for ${{\mathit g}^{eu}}$ = ${{\mathit g}}{}^{{{\mathit \mu}} {{\mathit c}}}$ = 1.
12  TUMASYAN 2021D search for energetic jets + $\not E_T$ events in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. The branching fraction for the decay of the leptoquark into an electron neutrino and up quark is assumed to be 100$\%$ ($\beta $ = 0). See their Fig. 12 for exclusion limits in mass-coupling plane.
13  DEY 2016 use the 2010-2012 IceCube PeV energy data set to constrain the leptoquark production cross section through the ${{\mathit \nu}}$ ${{\mathit q}}$ $\rightarrow$ LQ $\rightarrow$ ${{\mathit \nu}}{{\mathit q}}$ process. See their Figure 4 for the exclusion limit in the mass-coupling plane.
14  AARON 2011A search for various leptoquarks with lepton-flavor violating couplings. See their Figs.$~2 - 3$ and Tables$~1 - 4$ for detailed limits.
15  The quoted limit is for a scalar, weak isoscalar, charge $-1$/3 leptoquark coupled with ${{\mathit e}_{{{R}}}}$. See their Figs. $3 - 5$ for limits on states with different quantum numbers.
16  ABAZOV 2007E search for leptoquark single production through ${{\mathit q}}{{\mathit g}}$ fusion process in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions. See their Fig. 4 for exclusion plot in mass-coupling plane.
17  AKTAS 2005B limit is for a scalar, weak isoscalar, charge $−$1/3 leptoquark coupled with ${{\mathit e}_{{{R}}}}$. See their Fig. 3 for limits on states with different quantum numbers.
18  CHEKANOV 2005 search for various leptoquarks with lepton-flavor violating couplings. See their Figs.6--10 and Tables 1--8 for detailed limits.
19  CHEKANOV 2003B limit is for a scalar, weak isoscalar, charge $−$1/3 leptoquark coupled with ${{\mathit e}_{{{R}}}}$. See their Figs.$~11 - 12$ and Table$~$5 for limits on states with different quantum numbers.
20  For limits on states with different quantum numbers and the limits in the mass-coupling plane, see their Fig.$~$4 and Fig.$~$5.
21  CHEKANOV 2002 search for various leptoquarks with lepton-flavor violating couplings. See their Figs.$~6 - 7$ and Tables$~5 - 6$ for detailed limits.
22  For limits on states with different quantum numbers and the limits in the mass-coupling plane, see their Fig.$~$3.
23  See their Fig.$~$14 for limits in the mass-coupling plane.
24  BREITWEG 2000E search for $\mathit F$=0 leptoquarks in ${{\mathit e}^{+}}{{\mathit p}}$ collisions. For limits in mass-coupling plane, see their Fig.$~$11.
25  ABREU 1999G limit obtained from process ${{\mathit e}}$ ${{\mathit \gamma}}$ $\rightarrow\mathit LQ+q$. For limits on vector and scalar states with different quantum numbers and the limits in the coupling-mass plane, see their Fig.$~$4 and Table$~$2.
26  For limits on states with different quantum numbers and the limits in the mass-coupling plane, see their Fig.$~$13 and Fig.$~$14. ADLOFF 1999 also search for leptoquarks with lepton-flavor violating couplings. ADLOFF 1999 supersedes AID 1996B.
27  DERRICK 1997 search for various leptoquarks with lepton-flavor violating couplings. See their Figs.$~$5--8 and Table$~$1 for detailed limits.
28  DERRICK 1993 search for single leptoquark production in ${{\mathit e}}{{\mathit p}}$ collisions with the decay ${{\mathit e}}{{\mathit q}}$ and ${{\mathit \nu}}{{\mathit q}}$. The limit is for leptoquark coupling of electromagnetic strength and assumes B(${{\mathit e}}{{\mathit q}}$) = B(${{\mathit \nu}}{{\mathit q}}$) = 1/2. The limit for B(${{\mathit e}}{{\mathit q}}$) = 1 is 176 GeV. For limits on states with different quantum numbers, see their Table$~$3.
References