MASS LIMITS for Leptoquarks from Single Production

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
$> 550$ 95 1
 2021 J
CMS Third generation
$\bf{\text{none 150 - 740}}$ 95 2
 2018 BJ
CMS Third generation
$\bf{>1755}$ 95 3
 2016 AG
CMS First generation
$\bf{>660}$ 95 4
 2016 AG
CMS Second generation
$> 304$ 95 5
 2012 A
ZEUS First generation
$>73$ 95 6
 1993 J
DLPH Second generation
• • We do not use the following data for averages, fits, limits, etc. • •
7
 2021 D
CMS First generation
8
 2016
ICCB ${{\mathit \nu}}$ ${{\mathit q}}$ $\rightarrow$ LQ $\rightarrow$ ${{\mathit \nu}}{{\mathit q}}$
9
 2011 A
H1 Lepton-flavor violation
$> 300$ 95 10
 2011 B
H1 First generation
11
 2007 E
D0 Second generation
$> 295$ 95 12
 2005 B
H1 First generation
13
 2005 A
ZEUS Lepton-flavor violation
$>298$ 95 14
 2003 B
ZEUS First generation
$>197$ 95 15
 2002 B
OPAL First generation
16
 2002
ZEUS Repl. by CHEKANOV 2005A
$>290$ 95 17
 2001 C
H1 First generation
$>204$ 95 18
 2001
ZEUS First generation
19
 2000 E
ZEUS First generation
$>161$ 95 20
 1999 G
DLPH First generation
$>200$ 95 21
 1999
H1 First generation
22
 1997
ZEUS Lepton-flavor violation
$>168$ 95 23
 1993
ZEUS First generation
 1 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.
 2 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.
 3 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.
 4 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.
 5 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.
 6 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.
 7 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.
 8 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.
 9 AARON 2011A search for various leptoquarks with lepton-flavor violating couplings. See their Figs.$~2 - 3$ and Tables$~1 - 4$ for detailed limits.
 10 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.
 11 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.
 12 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.
 13 CHEKANOV 2005 search for various leptoquarks with lepton-flavor violating couplings. See their Figs.6--10 and Tables 1--8 for detailed limits.
 14 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$~$5 for limits on states with different quantum numbers.
 15 For limits on states with different quantum numbers and the limits in the mass-coupling plane, see their Fig.$~$4 and Fig.$~$5.
 16 CHEKANOV 2002 search for various leptoquarks with lepton-flavor violating couplings. See their Figs.$~6 - 7$ and Tables$~5 - 6$ for detailed limits.
 17 For limits on states with different quantum numbers and the limits in the mass-coupling plane, see their Fig.$~$3.
 18 See their Fig.$~$14 for limits in the mass-coupling plane.
 19 BREITWEG 2000E search for $\mathit F$=0 leptoquarks in ${{\mathit e}^{+}}{{\mathit p}}$ collisions. For limits in mass-coupling plane, see their Fig.$~$11.
 20 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.$~$4 and Table$~$2.
 21 For limits on states with different quantum numbers and the limits in the mass-coupling plane, see their Fig.$~$13 and Fig.$~$14. ADLOFF 1999 also search for leptoquarks with lepton-flavor violating couplings. ADLOFF 1999 supersedes AID 1996B.
 22 DERRICK 1997 search for various leptoquarks with lepton-flavor violating couplings. See their Figs.$~$5--8 and Table$~$1 for detailed limits.
 23 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:
 SIRUNYAN 2021J
PL B819 136446 Search for singly and pair-produced leptoquarks coupling to third-generation fermions in proton-proton collisions at $\sqrt{s} =$ 13 TeV
 TUMASYAN 2021D
JHEP 2111 153
 SIRUNYAN 2018BJ
JHEP 1807 115 Search for a singly produced third-generation scalar leptoquark decaying to a $\tau$ lepton and a bottom quark in proton-proton collisions at $\sqrt{s} =$ 13 TeV
 DEY 2016
JHEP 1604 187 Constraints on Leptoquark Models from IceCube Data
 KHACHATRYAN 2016AG
PR D93 032005 Search for Single Production of Scalar Leptoquarks in Proton-Proton Collisions at $\sqrt {s }$ = 8 TeV
 Also
PR D95 039906 (errat.) Erratum to KHACHATRYAN 2016AG: Search for Single Production of Scalar Leptoquarks in Proton-Proton Collisions at $\sqrt {s }$ = 8 TeV
 ABRAMOWICZ 2012A
PR D86 012005 Search for First-Generation Leptoquarks at HERA
 AARON 2011B
PL B704 388 Search for First Generation Leptoquarks in ${{\mathit e}}{{\mathit p}}$ Collisions at HERA
 AARON 2011A
PL B701 20 Search for Lepton Flavour Violation at HERA
 ABAZOV 2007E
PL B647 74 Search for Single Production of Scalar Leptoquarks in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions Decaying into Muons and Quarks with the ${D0}$ Detector
 AKTAS 2005B
PL B629 9 Search for Leptoquark Bosons in ${{\mathit e}}{{\mathit p}}$ Collisions at HERA
 CHEKANOV 2005A
EPJ C44 463 Search for Lepton-Flavor Violation at HERA
 CHEKANOV 2003B
PR D68 052004 A Search for Resonance Decays to Lepton + Jet at HERA and Limits on Leptoquarks
 ABBIENDI 2002B
PL B526 233 Search for Leptoquarks in Electron Photon Scattering at $\sqrt {s }_{ee}$ up to 209 GeV at LEP
 CHEKANOV 2002
PR D65 092004 Search for Lepton Flavor Violation in ${{\mathit e}^{+}}{{\mathit p}}$ Collisions at HERA
PL B523 234 A Search for Leptoquark Bosons in ${{\mathit e}^{-}}$ ${{\mathit p}}$ Collisions at HERA
 BREITWEG 2001
PR D63 052002 Search for Resonance Decays to an ${{\overline{\mathit \nu}}}$ plus Jet in ${{\mathit e}^{+}}$ ${{\mathit p}}$ Scattering at DESY HERA
 BREITWEG 2000E
EPJ C16 253 Search for Resonances Decaying to ${{\mathit e}^{+}}$ jet in ${{\mathit e}^{+}}$ ${{\mathit p}}$ Interactions at HERA
 ABREU 1999G
PL B446 62 Search for Leptoquarks and FCNC in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ Annihilations at $\sqrt {s }$ = 183 GeV
EPJ C11 447 A Search for Leptoquark Bosons and Lepton Flavor Violation in ${{\mathit e}^{+}}$ ${{\mathit p}}$ Collisions at HERA
EPJ C14 553 (errat.) Erratum: ADLOFF 1999 A Search for Leptoquark Bosons and Lepton Flavour Violation in ${{\mathit e}^{+}}$ ${{\mathit p}}$ Collisions at HERA
ZPHY C73 613 Search for Lepton Flavor Violation in ${{\mathit e}}{{\mathit p}}$ Collisions at 300 GeV Center of Mass Energy
PL B316 620 Limits on the Production of Scalar Leptoquarks from ${{\mathit Z}^{0}}$ Decays at LEP