Indirect Limits for Leptoquarks

INSPIRE   PDGID:
S056LQI
VALUE (TeV) CL% DOCUMENT ID TECN  COMMENT
• • We do not use the following data for averages, fits, limits, etc. • •
1
CALABRESE
2023
RVUE ${{\mathit \nu}}$-nucleus scattering
2
TUMASYAN
2023AW
CMS ${{\mathit q}}$ ${{\overline{\mathit q}}^{\,'}}$ $\rightarrow$ ${{\mathit \tau}}{{\mathit \nu}}$
3
TUMASYAN
2023S
CMS ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \tau}}{{\mathit \tau}}$
4
CRIVELLIN
2021A
RVUE First generation
5
AEBISCHER
2020
RVUE ${{\mathit B}}$ decays
6
DEPPISCH
2020
RVUE ${{\mathit K}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \nu}}{{\mathit \nu}}$
$> 3.1$ 95 7
ABRAMOWICZ
2019
ZEUS First generation
8
MANDAL
2019
RVUE ${{\mathit \tau}}$, ${{\mathit \mu}}$, ${{\mathit e}}$, ${{\mathit K}}$
9
ZHANG
2018A
RVUE ${{\mathit D}}$ decays
10
BARRANCO
2016
RVUE ${{\mathit D}}$ decays
11
KUMAR
2016
RVUE neutral ${{\mathit K}}$ mixing, rare ${{\mathit K}}$ decays
12
BESSAA
2015
RVUE ${{\mathit q}}$ ${{\overline{\mathit q}}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$
$\text{> 14}$ 95 13
SAHOO
2015A
RVUE ${{\mathit B}}$ $_{s,d}$ $\rightarrow$ ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
14
SAKAKI
2013
RVUE ${{\mathit B}}$ $\rightarrow$ ${{\mathit D}^{(*)}}{{\mathit \tau}}{{\overline{\mathit \nu}}}$, ${{\mathit B}}$ $\rightarrow$ ${{\mathit X}_{{{s}}}}{{\mathit \nu}}{{\overline{\mathit \nu}}}$
15
KOSNIK
2012
RVUE ${{\mathit b}}$ $\rightarrow$ ${{\mathit s}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$
$> 2.5$ 95 16
AARON
2011C
H1 First generation
17
DORSNER
2011
RVUE scalar, weak singlet, charge 4/3
18
AKTAS
2007A
H1 Lepton-flavor violation
$> 0.49$ 95 19
SCHAEL
2007A
ALEP ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$
20
SMIRNOV
2007
RVUE ${{\mathit K}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$, ${{\mathit B}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \tau}}$
21
CHEKANOV
2005A
ZEUS Lepton-flavor violation
$>1.7$ 96 22
ADLOFF
2003
H1 First generation
$> 46$ 90 23
CHANG
2003
BELL Pati-Salam type
24
CHEKANOV
2002
ZEUS Repl. by CHEKANOV 2005A
$>1.7$ 95 25
CHEUNG
2001B
RVUE First generation
$>0.39$ 95 26
ACCIARRI
2000P
L3 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\mathit q}}$
$>1.5$ 95 27
ADLOFF
2000
H1 First generation
$>0.2$ 95 28
BARATE
2000I
ALEP Repl. by SCHAEL 2007A
29
BARGER
2000
RVUE ${}^{}\mathrm {Cs}$
30
GABRIELLI
2000
RVUE Lepton flavor violation
$>0.74$ 95 31
ZARNECKI
2000
RVUE $\mathit S_{1}$ leptoquark
32
ABBIENDI
1999
OPAL
$>19.3$ 95 33
ABE
1998V
CDF ${{\mathit B}_{{{s}}}}$ $\rightarrow$ ${{\mathit e}^{\pm}}{{\mathit \mu}^{\mp}}$, Pati-Salam type
34
ACCIARRI
1998J
L3 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$
35
ACKERSTAFF
1998V
OPAL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$, ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}$
$>0.76$ 95 36
DEANDREA
1997
RVUE ${{\widetilde{\mathit R}}_{{{2}}}}$ leptoquark
37
DERRICK
1997
ZEUS Lepton-flavor violation
38
GROSSMAN
1997
RVUE ${{\mathit B}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ (X)
39
JADACH
1997
RVUE ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$
$>1200$ 40
KUZNETSOV
1995B
RVUE Pati-Salam type
41
MIZUKOSHI
1995
RVUE Third generation scalar leptoquark
$>0.3$ 95 42
BHATTACHARYYA
1994
RVUE Spin-0 leptoquark coupled to ${{\overline{\mathit e}}_{{{R}}}}{{\mathit t}_{{{L}}}}$
43
DAVIDSON
1994
RVUE
$>18$ 44
KUZNETSOV
1994
RVUE Pati-Salam type
$>0.43$ 95 45
LEURER
1994
RVUE First generation spin-1 leptoquark
$>0.44$ 95 45
LEURER
1994B
RVUE First generation spin-0 leptoquark
46
MAHANTA
1994
RVUE $\mathit P$ and $\mathit T$ violation
$>1$ 47
SHANKER
1982
RVUE Nonchiral spin-0 leptoquark
$>125$ 47
SHANKER
1982
RVUE Nonchiral spin-1 leptoquark
1  CALABRESE 2023 obtain limits on leptoquark coupling from coherent ${{\mathit \nu}}$-nucleus scattering data collected by COHERENT experiment. See their Fig. 3 for limits in mass-coupling plane.
2  TUMASYAN 2023AW search for ${{\mathit \tau}}{{\mathit \nu}}$ events mediated by ${{\mathit t}}$-channel leptoquark exchange in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. See their Fig. 10 for limits in mass-coupling plane.
3  TUMASYAN 2023S search for leptoquark induced ${{\mathit b}}$ ${{\overline{\mathit b}}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ process in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV. See their Fig. 12 for limits on a vector ${{\mathit b}}{{\mathit \tau}}$ leptoquark in mass-coupling plane.
4  CRIVELLIN 2021A set limits on coupling strengths of scalar and vector leptoquarks using ${{\mathit K}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \nu}}{{\mathit \nu}}$, ${{\mathit K}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit e}^{+}}{{\mathit e}^{-}}$, ${{\mathit K}^{0}}−{{\overline{\mathit K}}^{0}}$ and ${{\mathit D}^{0}}−{{\overline{\mathit D}}^{0}}$ mixings, and weak neutral current measurements. See their Fig. 2 and Fig. 3 for the limits in mass-coupling plane.
5  AEBISCHER 2020 explain the ${{\mathit B}}$ decay anomalies using four-fermion operator Wilson coefficents. See their Table 1. These Wilson coefficients may be generated by a ${{\mathit U}_{{{1}}}}$ vector leptoquark with ${{\mathit U}_{{{1}}}}$ transforming as (3,1)$_{2/3}$ under the SM gauge group. See their Figures 6, 7, 8 for the regions of the LQ parameter space which explains the ${{\mathit B}}$ anomalies and avoids the indirect low energy constraints.
6  DEPPISCH 2020 limits on the lepton-number-violating higher-dimensional-operators are derived from ${{\mathit K}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \nu}}{{\mathit \nu}}$ in the standard model effective field theory. These higher-dimensional-operators may be induced from leptoquark-exchange diagrams.
7  ABRAMOWICZ 2019 obtain a limit on $\lambda /{{\mathit M}_{{{LQ}}}}$ $>$ 1.16 TeV${}^{-1}$ for weak isotriplet spin-0 leptoquark ${{\mathit S}_{{{1}}}^{L}}$. We obtain the limit quoted above by converting the limit on $\lambda /{{\mathit M}_{{{LQ}}}}$ for ${{\mathit S}_{{{1}}}^{L}}$ assuming $\lambda $ = $\sqrt {4 \pi }$. See their Table 5 for the limits of leptoquarks with different quantum numbers. These limits are derived from bounds of ${{\mathit e}}{{\mathit q}}$ contact interactions.
8  MANDAL 2019 give bounds on leptoquarks from ${{\mathit \tau}}$-decays, leptonic dipole moments, lepton-flavor-violating processes, and ${{\mathit K}}$ decays.
9  ZHANG 2018A give bounds on leptoquark induced four-fermion interactions from ${{\mathit D}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \ell}}{{\mathit \nu}}$. The authors inform us that the shape parameter of the vector form factor in both the abstract and the conclusions of ZHANG 2018A should be $\mathit r_{+1}$ = $2.16$ $\pm0.07$ rather than $\pm0.007$. The numbers listed in their Table 7 are correct.
10  BARRANCO 2016 give bounds on leptoquark induced four-fermion interactions from ${{\mathit D}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \ell}}{{\mathit \nu}}$ and ${{\mathit D}_{{{s}}}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \nu}}$.
11  KUMAR 2016 gives bound on SU(2) singlet scalar leptoquark with chrge $−$1/3 from ${{\mathit K}^{0}}−{{\overline{\mathit K}}^{0}}$ mixing, ${{\mathit K}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \nu}}{{\overline{\mathit \nu}}}$, ${{\mathit K}_L^0}$ $\rightarrow$ ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$, and ${{\mathit K}_L^0}$ $\rightarrow$ ${{\mathit \mu}^{\pm}}{{\mathit e}^{\mp}}$ decays.
12  BESSAA 2015 obtain limit on leptoquark induced four-fermion interactions from the ATLAS and CMS limit on the ${{\overline{\mathit q}}}{{\mathit q}}{{\overline{\mathit e}}}{{\mathit e}}$ contact interactions.
13  SAHOO 2015A obtain limit on leptoquark induced four-fermion interactions from ${{\mathit B}}$ $_{s,d}$ $\rightarrow$ ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$ for $\lambda $ $\simeq{}$ $\mathit O$(1).
14  SAKAKI 2013 explain the ${{\mathit B}}$ $\rightarrow$ ${{\mathit D}^{(*)}}{{\mathit \tau}}{{\overline{\mathit \nu}}}$ anomaly using Wilson coefficients of leptoquark-induced four-fermion operators.
15  KOSNIK 2012 obtains limits on leptoquark induced four-fermion interactions from ${{\mathit b}}$ $\rightarrow$ ${{\mathit s}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ decays.
16  AARON 2011C limit is for weak isotriplet spin-0 leptoquark at strong coupling ${{\mathit \lambda}}$ = $\sqrt {4\pi }$. For the limits of leptoquarks with different quantum numbers, see their Table 3. Limits are derived from bounds of ${{\mathit e}}{{\mathit q}}$ contact intereractions.
17  DORSNER 2011 give bounds on scalar, weak singlet, charge 4/3 leptoquark from ${{\mathit K}}$, ${{\mathit B}}$, ${{\mathit \tau}}$ decays, meson mixings, $\mathit LFV$, $\mathit g−$2 and ${{\mathit Z}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}$.
18  AKTAS 2007A search for lepton-flavor violation in ${{\mathit e}}{{\mathit p}}$ collision. See their Tables $4 - 7$ for limits on lepton-flavor violating four-fermion interactions induced by various leptoquarks.
19  SCHAEL 2007A limit is for the weak-isoscalar spin-0 left-handed leptoquark with the coupling of electromagnetic strength. For the limits of leptoquarks with different quantum numbers, see their Table 35.
20  SMIRNOV 2007 obtains mass limits for the vector and scalar chiral leptoquark states from ${{\mathit K}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$, ${{\mathit B}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \tau}}$ decays.
21  CHEKANOV 2005 search for various leptoquarks with lepton-flavor violating couplings. See their Figs.6--10 and Tables 1--8 for detailed limits.
22  ADLOFF 2003 limit is for the weak isotriplet spin-0 leptoquark at strong coupling $\lambda =\sqrt {4{{\mathit \pi}} }$. For the limits of leptoquarks with different quantum numbers, see their Table$~$3. Limits are derived from bounds on ${{\mathit e}^{\pm}}{{\mathit q}}$ contact interactions.
23  The bound is derived from B( ${{\mathit B}^{0}}$ $\rightarrow$ ${{\mathit e}^{\pm}}{{\mathit \mu}^{\mp}}$) $<$ $1.7 \times 10^{-7}$.
24  CHEKANOV 2002 search for lepton-flavor violation in ${{\mathit e}}{{\mathit p}}$ collisions. See their Tables$~1 - 4$ for limits on lepton-flavor violating and four-fermion interactions induced by various leptoquarks.
25  CHEUNG 2001B quoted limit is for a scalar, weak isoscalar, charge $−$1/3 leptoquark with a coupling of electromagnetic strength. The limit is derived from bounds on contact interactions in a global electroweak analysis. For the limits of leptoquarks with different quantum numbers, see Table$~$5.
26  ACCIARRI 2000P limit is for the weak isoscalar spin-0 leptoquark with the coupling of electromagnetic strength. For the limits of leptoquarks with different quantum numbers, see their Table$~$4.
27  ADLOFF 2000 limit is for the weak isotriplet spin-0 leptoquark at strong coupling, $\lambda =\sqrt {4\pi }$. For the limits of leptoquarks with different quantum numbers, see their Table$~$2. ADLOFF 2000 limits are from the $\mathit Q{}^{2}$ spectrum measurement of ${{\mathit e}^{+}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit e}^{+}}$ X.
28  BARATE 2000I search for deviations in cross section and jet-charge asymmetry in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\overline{\mathit q}}}{{\mathit q}}$ due to $\mathit t$-channel exchange of a leptoquark at $\sqrt {\mathit s }$=130 to 183 GeV. Limits for other scalar and vector leptoquarks are also given in their Table$~$22.
29  BARGER 2000 explain the deviation of atomic parity violation in cesium atoms from prediction is explained by scalar leptoquark exchange.
30  GABRIELLI 2000 calculate various process with lepton flavor violation in leptoquark models.
31  ZARNECKI 2000 limit is derived from data of HERA, LEP, and Tevatron and from various low-energy data including atomic parity violation. Leptoquark coupling with electromagnetic strength is assumed.
32  ABBIENDI 1999 limits are from ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$ cross section at $130 - 136$, $161 - 172$, 183 GeV. See their Fig.$~$8 and Fig.$~$9 for limits in mass-coupling plane.
33  ABE 1998V quoted limit is from B( ${{\mathit B}_{{{s}}}}$ $\rightarrow$ ${{\mathit e}^{\pm}}{{\mathit \mu}^{\mp}})<8.2 \times 10^{-6}$. ABE 1998V also obtain a similar limit on $\mathit M_{LQ}>20.4$ TeV from B( ${{\mathit B}_{{{d}}}}$ $\rightarrow$ ${{\mathit e}^{\pm}}{{\mathit \mu}^{\mp}})<4.5 \times 10^{-6}$. Both bounds assume the non-canonical association of the ${{\mathit b}}~$quark with electrons or muons under SU(4).
34  ACCIARRI 1998J limit is from ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$ cross section at $\sqrt {\mathit s }$= $130 - 172$ GeV which can be affected by the ${{\mathit t}}-~$and ${{\mathit u}}$-channel exchanges of leptoquarks. See their Fig.$~$4 and Fig.$~$5 for limits in the mass-coupling plane.
35  ACKERSTAFF 1998V limits are from ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$ and ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}$ cross sections at $\sqrt {\mathit s }$ = $130 - 172$ GeV, which can be affected by the $\mathit t$- and $\mathit u$-channel exchanges of leptoquarks. See their Fig.$~$21 and Fig.$~$22 for limits of leptoquarks in mass-coupling plane.
36  DEANDREA 1997 limit is for ${{\widetilde{\mathit R}}_{{{2}}}}$ leptoquark obtained from atomic parity violation (APV). The coupling of leptoquark is assumed to be electromagnetic strength. See Table$~$2 for limits of the four-fermion interactions induced by various scalar leptoquark exchange. DEANDREA 1997 combines APV limit and limits from Tevatron and HERA. See Fig.$~1 - 4$ for combined limits of leptoquark in mass-coupling plane.
37  DERRICK 1997 search for lepton-flavor violation in ${{\mathit e}}{{\mathit p}}$ collision. See their Tables$~$2--5 for limits on lepton-flavor violating four-fermion interactions induced by various leptoquarks.
38  GROSSMAN 1997 estimate the upper bounds on the branching fraction ${{\mathit B}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ (X) from the absence of the ${{\mathit B}}$ decay with large missing energy. These bounds can be used to constrain leptoquark induced four-fermion interactions.
39  JADACH 1997 limit is from ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$ cross section at $\sqrt {\mathit s }=172.3$ GeV which can be affected by the ${{\mathit t}}$- and ${{\mathit u}}$-channel exchanges of leptoquarks. See their Fig.$~$1 for limits on vector leptoquarks in mass-coupling plane.
40  KUZNETSOV 1995B use ${{\mathit \pi}}$, ${{\mathit K}}$, ${{\mathit B}}$, ${{\mathit \tau}}$ decays and ${{\mathit \mu}}{{\mathit e}}$ conversion and give a list of bounds on the leptoquark mass and the fermion mixing matrix in the Pati-Salam model. The quoted limit is from ${{\mathit K}_{{{L}}}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit e}}$ decay assuming zero mixing.
41  MIZUKOSHI 1995 calculate the one-loop radiative correction to the ${{\mathit Z}}$-physics parameters in various scalar leptoquark models. See their Fig.$~$4 for the exclusion plot of third generation leptoquark models in mass-coupling plane.
42  BHATTACHARYYA 1994 limit is from one-loop radiative correction to the leptonic decay width of the ${{\mathit Z}}$. ${\mathit m}_{{{\mathit H}}}$=250 GeV, ${{\mathit \alpha}_{{{s}}}}({\mathit m}_{{{\mathit Z}}})=0.12$, ${\mathit m}_{{{\mathit t}}}$=180 GeV, and the electroweak strength of leptoquark coupling are assumed. For leptoquark coupled to ${{\overline{\mathit e}}_{{{L}}}}{{\mathit t}_{{{R}}}}$, ${{\overline{\mathit \mu}}}{{\mathit t}}$, and ${{\overline{\mathit \tau}}}{{\mathit t}}$, see Fig.$~$2 in BHATTACHARYYA 1994B erratum and Fig.$~$3.
43  DAVIDSON 1994 gives an extensive list of the bounds on leptoquark-induced four-fermion interactions from ${{\mathit \pi}}$, ${{\mathit K}}$, ${{\mathit D}}$, ${{\mathit B}}$, ${{\mathit \mu}}$, ${{\mathit \tau}}$ decays and meson mixings, $\mathit etc$. See Table$~$15 of DAVIDSON 1994 for detail.
44  KUZNETSOV 1994 gives mixing independent bound of the Pati-Salam leptoquark from the cosmological limit on ${{\mathit \pi}^{0}}$ $\rightarrow$ ${{\overline{\mathit \nu}}}{{\mathit \nu}}$.
45  LEURER 1994, LEURER 1994B limits are obtained from atomic parity violation and apply to any chiral leptoquark which couples to the first generation with electromagnetic strength. For a nonchiral leptoquark, universality in ${{\mathit \pi}}_{{{\mathit \ell}}2}$ decay provides a much more stringent bound.
46  MAHANTA 1994 gives bounds of $\mathit P$- and $\mathit T$-violating scalar-leptoquark couplings from atomic and molecular experiments.
47  From ( ${{\mathit \pi}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \nu}})/$( ${{\mathit \pi}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit \nu}}$) ratio. SHANKER 1982 assumes the leptoquark induced four-fermion coupling 4$\mathit g{}^{2}/\mathit M{}^{2}$ (${{\overline{\mathit \nu}}}_{\mathit eL}$ $\mathit u_{\mathit R}$) (${{\overline{\mathit d}}_{{{L}}}}{{\mathit e}_{{{R}}}}$)with $\mathit g=0.004$ for spin-0 leptoquark and $\mathit g{}^{2}/\mathit M{}^{2}$ (${{\overline{\mathit \nu}}}_{\mathit eL}{{\mathit \gamma}_{{{\mu}}}}{{\mathit u}_{{{L}}}}$) (${{\overline{\mathit d}}_{{{R}}}}{{\mathit \gamma}}{}^{{{\mathit \mu}}}$ ${{\mathit e}_{{{R}}}}$) with $\mathit g≅0.6$ for spin-1 leptoquark.
References