t-t-h, Top & Bottom Partners, and the Brane Higgs Limit
607
3 Outlook
We have presented a simple explanation of possible enhancements in the t ¯
th associated production, with the effect decoupled from deviations in Higgs production
through gluon fusion at the LHC. This was possible by the addition of vector-like
top and bottom partners whose main effect is to modify the top and bottom quark
Yukawa couplings and thus potentially modify the cross section for t ¯
th production.
In general the effect should also affect the cross section for Higgs production
through gluon fusion but we showed that working in a particular limit of parameter
space, the Brane Higgs limit, the corrections to gluon fusion caused by the top
Yukawa coupling variations are exactly offset by the contributions of the new top
partners, thus keeping the cross section under control (and only depending on
variations of the bottom quark Yukawa coupling!).
Essentially the scenario manages to decouple possible deviations on gluon fusion
production from deviations in tth production, which are usually expected to be
directly connected. We showed how the scenario links and constrains theoretically
all the possible deviations making the scenario easily falsifiable in the coming high
luminosity runs at the LHC.
Acknowledgments I would like to thank FRQNT for partial financial support under grant number
PRCC-191578 as well as Dawson College for support from the professional development fund.
I would also like to thank Gilles Couture, Mariana Frank, and Cherif Hamzaoui for fruitful
discussions and collaborations.
References
1. M. Aaboud et al. [ATLAS], Phys. Lett. B 784, 173–191 (2018)
2. A.M. Sirunyan et al. (CMS Collaboration), Phys. Rev. Lett. 120, 23180 (2018)
3. [ATLAS], Measurement of Higgs boson production in association with a tt pair in the diphoton
decay channel using 139 fb −1 of LHC data collected at
√
s = 13 TeV by the ATLAS
experiment, ATLAS-CONF-2019-004 (March 2019)
4. A.M. Sirunyan et al. [CMS], Measurements of t¯ tH production and the CP structure of the
Yukawa interaction between the Higgs boson and top quark in the diphoton decay channel.
arXiv:2003.10866 [hep-ex] (March 2020)
5. D. Choudhury, T.M.P. Tait, C.E.M. Wagner, Phys. Rev. D 65, 053002 (2002); D.E. Morrissey,
C.E.M. Wagner, Phys. Rev. D 69, 053001 (2004)
6. G. Couture, M. Frank, C. Hamzaoui, M. Toharia, Phys. Rev. D 95(9), 095038 (2017)
7. M. Aaboud et al. [ATLAS], Phys. Rev. D 98(11), 112010 (2018)
8. A. Azatov, M. Toharia, L. Zhu, Phys. Rev. D 80, 035016 (2009)
9. J.F. Gunion, H.E. Haber, G.L. Kane, S. Dawson, Front. Phys. 80, 1 (2000)
10. L. Randall, R. Sundrum, Phys. Rev. Lett. 83, 3370 (1999); ibid., Phys. Rev. Lett. 83, 4690
(1999)
607
3 Outlook
We have presented a simple explanation of possible enhancements in the t ¯
th associated production, with the effect decoupled from deviations in Higgs production
through gluon fusion at the LHC. This was possible by the addition of vector-like
top and bottom partners whose main effect is to modify the top and bottom quark
Yukawa couplings and thus potentially modify the cross section for t ¯
th production.
In general the effect should also affect the cross section for Higgs production
through gluon fusion but we showed that working in a particular limit of parameter
space, the Brane Higgs limit, the corrections to gluon fusion caused by the top
Yukawa coupling variations are exactly offset by the contributions of the new top
partners, thus keeping the cross section under control (and only depending on
variations of the bottom quark Yukawa coupling!).
Essentially the scenario manages to decouple possible deviations on gluon fusion
production from deviations in tth production, which are usually expected to be
directly connected. We showed how the scenario links and constrains theoretically
all the possible deviations making the scenario easily falsifiable in the coming high
luminosity runs at the LHC.
Acknowledgments I would like to thank FRQNT for partial financial support under grant number
PRCC-191578 as well as Dawson College for support from the professional development fund.
I would also like to thank Gilles Couture, Mariana Frank, and Cherif Hamzaoui for fruitful
discussions and collaborations.
References
1. M. Aaboud et al. [ATLAS], Phys. Lett. B 784, 173–191 (2018)
2. A.M. Sirunyan et al. (CMS Collaboration), Phys. Rev. Lett. 120, 23180 (2018)
3. [ATLAS], Measurement of Higgs boson production in association with a tt pair in the diphoton
decay channel using 139 fb −1 of LHC data collected at
√
s = 13 TeV by the ATLAS
experiment, ATLAS-CONF-2019-004 (March 2019)
4. A.M. Sirunyan et al. [CMS], Measurements of t¯ tH production and the CP structure of the
Yukawa interaction between the Higgs boson and top quark in the diphoton decay channel.
arXiv:2003.10866 [hep-ex] (March 2020)
5. D. Choudhury, T.M.P. Tait, C.E.M. Wagner, Phys. Rev. D 65, 053002 (2002); D.E. Morrissey,
C.E.M. Wagner, Phys. Rev. D 69, 053001 (2004)
6. G. Couture, M. Frank, C. Hamzaoui, M. Toharia, Phys. Rev. D 95(9), 095038 (2017)
7. M. Aaboud et al. [ATLAS], Phys. Rev. D 98(11), 112010 (2018)
8. A. Azatov, M. Toharia, L. Zhu, Phys. Rev. D 80, 035016 (2009)
9. J.F. Gunion, H.E. Haber, G.L. Kane, S. Dawson, Front. Phys. 80, 1 (2000)
10. L. Randall, R. Sundrum, Phys. Rev. Lett. 83, 3370 (1999); ibid., Phys. Rev. Lett. 83, 4690
(1999)