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2019:groups:higgs:gildener [2019/10/30 16:03]
jonathan.butterworth
2019:groups:higgs:gildener [2019/10/30 17:06]
jonathan.butterworth
Line 24: Line 24:
 === Scanning the parameter space === === Scanning the parameter space ===
  
-Fix the m(h+/-) and A masses to be equal to $M$ and related to the $H^\prime$ mass via $(540 GeV)^4 = M_{H^\prime}^4 + 3M^4$, and scan over $0.1 < \tan\beta < 10$ and $150 < M < 410$GeV.+Fix the $h^\pm$ and $Amasses to be equal to $M$ and related to the $H^\prime$ mass via $(540 GeV)^4 = M_{H^\prime}^4 + 3M^4$, and scan over $0.1 < \tan\beta < 10$ and $150 < M < 410$GeV.
  
-KL: The reason for M(h+/-) = M(h3) is that this makes the BSM Higgses'​ contribution to the T-parameter vanish ​through ​one-loop order. (See Lee & Pilaftsis, PRD 86, 035004 (2012) and the KL-WS PRD cited above.) ​+KL: The reason for $M(h^\pm) = M(h_3)is that this makes the BSM Higgses'​ contribution to the T-parameter vanish ​to one-loop order. (See Lee & Pilaftsis, PRD 86, 035004 (2012) and the KL-WS PRD cited above.) ​
 It would be interesting to investigate how much this mass equality can be relaxed and remain consistent with the T-parameter constraint. It would be interesting to investigate how much this mass equality can be relaxed and remain consistent with the T-parameter constraint.
  
-KL: The sum rule constraint for this model, (M^4_{h2} + M^4_{h3} + 2M^4_{h+})^{1/​4} = 540 GeV, follows from the Higgs-mass (M_{h1}) formula derived by E. Gildener and S. Weinberg in PRD 13, 3333 (1976). It is determined by minimizing the one-loop approximation to the S. Coleman--E. Weinberg potential for this model. Because of this sum rule constraint, when M_{h+M_{h3} ​\simge 400 GeV, the mass M_{h2} ​and various branching ratios of h+/- and h3 are very sensitive to small changes in M_{h+M_h3}. Especially the BR's for h+/- -> W+/- h2 and h3 -> h2 grow rapidly and become more important than t bbar and t tbar, respectively.+KL: The sum rule constraint for this model, ($M^4_{h_2} + M^4_{h_3} + 2M^4_{h^+})^{1/4} = 540GeV, follows from the Higgs-mass ($M({h_1}$) formula derived by E. Gildener and S. Weinberg in PRD 13, 3333 (1976). It is determined by minimizing the one-loop approximation to the S. Coleman--E. Weinberg potential for this model. Because of this sum rule constraint, when $M(h^+M(h_3) ​\simge 400GeV, the mass $M(h_2)$ ​and various branching ratios of $h^\pm$ and $h_3$ are very sensitive to small changes in $M(h^+M(h_3)$. Especially the BR's for $h^\pm \rightarrow ​W^\pm h_2$ and $h_3 \rightarrow ​h_2$ grow rapidly and become more important than $\bar{b}$ ​and $\bar{b}$, respectively.
 Therefore, it is interesting and important to see how much the sum rule is affected by, e.g., the two-loop correction to the effective potential. That is, how seriously we should take the 540 GeV RHS of the sum rule? Therefore, it is interesting and important to see how much the sum rule is affected by, e.g., the two-loop correction to the effective potential. That is, how seriously we should take the 540 GeV RHS of the sum rule?
  
 {{:​2019:​groups:​higgs:​combinedhybrid2hdm_lh2.png?​500|}} {{:​2019:​groups:​higgs:​combinedhybrid2hdm_lh2.png?​500|}}
 +
 +Explanation of the legend: ​
 +On the left, yellow means excluded at 95% c.l. or more, green at 68%-95% (ie 2 and 1 sigma).
 +On the right, the same exclusions are shown but on a continuous scale (indicated by the bar on the right) with
 +1 being fully excluded, 0 being zero sensitivity.
 +
  
 As you can see, the measurements disfavour $\tan\beta > 1$ regardless of $M = M_A$. There is some increase in sensitivity at high $M_A$. We can also plot the same data as a function of $M_{H^\prime}$:​ As you can see, the measurements disfavour $\tan\beta > 1$ regardless of $M = M_A$. There is some increase in sensitivity at high $M_A$. We can also plot the same data as a function of $M_{H^\prime}$:​
2019/groups/higgs/gildener.txt ยท Last modified: 2019/10/31 12:58 by jonathan.butterworth