Abstract
Abstract Light states associated with the hierarchy problem affect the Higgs LHC production and decays. We illustrate this within the MSSM and two simple extensions applying the latest bounds from LHC Higgs searches. Large deviations in the Higgs properties are expected in a natural SUSY spectrum. The discovery of a non-Standard-Model Higgs may signal the presence of light stops accessible at the LHC. Conversely, the more the Higgs is Standard-Model-like, the more tuned the theory becomes. Taking the ratio of different Higgs decay channels at the LHC cancels the leading QCD uncertainties and potentially improves the accuracy in Higgs coupling measurements to the percent level. This may lead to the possibility of doing precision Higgs physics at the LHC. Finally, we entertain the possibility that the ATLAS excess around 125 GeV persists with a Higgs production cross-section that is enhanced compared to the SM. This increase can only be accommodated in extensions of the MSSM and it may suggest that stops lie below 400 GeV, likely within reach of next year’s LHC run.
Highlights
The same is true for one of the most important Higgs decay channels, h → γγ
How natural is SUSY, though, given the absence of any significant deviation from the SM? Within the minimal implementation of SUSY (MSSM), the LEP bounds on the Higgs mass increase the fine-tuning to an uncomfortable level, but this problem is solved in simple extensions of the MSSM
In the rest of the paper, we will consider, besides the case of an MSSM Higgs, two other cases: 1) MSSM with extra D-terms (DMSSM), where an extra quartic term for the Higgs is generated by an additional gauge sector that is broken above the electroweak scale [26], and 2) NMSSM [27](λSU SY [28, 29]), where the extra contribution to the Higgs mass comes from an extra singlet
Summary
The light Higgs mass in the MSSM is naturally constrained to lie below the Z mass at tree level. Light stops increase the LHC Higgs production crosssection [11,12,13,14,15], since the latter is related to the β-function of αs to which scalar fields contribute with the same sign as fermions [16, 17] This behavior persists after SUSY breaking in the absence of stop mixing, while a large mixing between the stop eigenstates interferes destructively with the top loop and the gluon fusion process can be suppressed substantially. This expansion shows that mixing becomes important for a light Higgs between 115 and ∼150 GeV, when the BR to bb is dominant Mixing in this case can suppress the Higgs cross-section in a given channel compared to the SM value significantly (more than 20%) when mA is lighter than roughly 400 GeV. In the rest of the paper, we will consider, besides the case of an MSSM Higgs, two other cases: 1) MSSM with extra D-terms (DMSSM), where an extra quartic term for the Higgs is generated by an additional gauge sector that is broken above the electroweak scale [26], and 2) NMSSM [27](λSU SY [28, 29]), where the extra contribution to the Higgs mass comes from an extra singlet (with possibly large couplings)
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