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2015:groups:higgs:morehiggs:largesplit [2015/06/13 15:32]
2015:groups:higgs:morehiggs:largesplit [2015/06/18 18:09]
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 **Responsible:​** Jose Mi No  ​ **Responsible:​** Jose Mi No  ​
-**Members:​** Ken Mimasu, Werner Porod, Jérémy Bernon, Andrey Katz, Dipan Sengupta+**Members:​** Ken Mimasu, Werner Porod, Jérémy Bernon, Andrey Katz, Dipan Sengupta, Sanjoy Biswas
-**Idea**:+In the context of 2HDM, there is no a priory reason to expect that the neutral states A0, H0 should be close in mass, only one of the two has to be relatively close in mass to H+ due to T-parameter constraints. When |m_A0 - m_H0| > m_Z and/or |m_H+ - m_{H0/A0}| > m_W, various possible decays open(depending on the spectrum) A0 -> H0 Z, H0 -> A0 Z, H+ -> H0 W+, H+ -> A0 W+, A0 -> H+ W-, H0 -> H+ W- (other possible non-SM decays which appear for a sizable mass splitting are H0 -> A0 A0 and H0 -> H+ H-). 
-What are the current 8 TeV LHC constraints and 13/14 TeV LHC prospects for new scalars with sizable mass splittingssuch that decays H1 -> H2 V or H1 -> H2 H2 are important/​dominant? ​+These decays typically dominate ​the Br of the mother particle when the splitting is largeon one side weakening searches of the mother particle via other Br, on the other providing a new discovery mode for both mother and daughter particles (usually very clean). ​   ​
-Let's consider the above idea more concretely in the context of 2HDM. There is no priory reason ​to expect that the neutral states A0, H0 should be close in mass (one of the two has to relatively close in mass to H+ due to T-parameter constraints). When |m_A0 m_H0| m_Z, either decay A0 -> H0 Z or H0 -> A0 Z becomes available +  * Assume light A0 scenario for 2HDM (m_A0 < 100 GeV, e.g. [[http://​​abs/​1412.3385]]). For TypeII 2HDM, a large splitting m_H0 - m_A0 ~ 200-300 GeV is required. For TypeI 2HDM, sizable m_H0 - m_A0 is not required but perfectly possible. In both cases, g g -> H0 -> Z A0 -> ll bb could probe this scenario for low tan_beta (< 5) as complementary search ​to bbA0 ([[2015:​groups:​higgs:​morehiggs:​lowmassa]]). 
 +  * Use [[http://​​record/​2014119]] to extract ​the limits on tan_beta ​in the (m_A0,m_H0) plane, ​in the 2HDM alignment limit: 
 +      The plot below shows the excluded regions for Type I (leftand Type II (right): (red -> t_beta = 0.5; blue -> t_beta = 1; orange ​-> t_beta = 1.5; green -> t_beta = 2) 
 + ​{{:​2015:​groups:​higgs:​morehiggs:​h0toa0ztriangle.jpeg?​direct&​300|}} {{:​2015:​groups:​higgs:​morehiggs:​h0toa0ztriangle_type2.jpeg?​direct&​300|}}
 +Regarding the interplay/​contamination of bbH0 in the gg channel... ​
 +     * LHC14 Prospects and interplay with bbA0
 +      ​
 **Literature**:​ **Literature**:​
 +**__Light A/H__**:
 +  * [[http://​​abs/​1412.3385]]:​ A detailed analysis of the 2HDM allowed region for a light A0 (20 GeV < m_A0 < 60 GeV), both in TypeI and TypeII. It also has a discussion of detection prospects in bbA0 and gg->A0 for "​aligment"​ and "​wrong-sign"​ scenarios, showing that in particular for TypeII the "​wrong-sign"​ can be completely explored with bbA0.  ​
 +**__Sizable Splitting in 2HDM and A->​ZH/​H->​ZA__**:​
 +  * [[http://​​record/​2014119]]:​ CMS has recently carried on a search of A0 -> Z H0 / H0 -> Z A0 in ll bb, ll tautau final states. This search constraints values of tan_beta up to 4 for some (m_A0, m_H0) values with a sizable splitting.
 +  * [[http://​​abs/​1405.5537]]:​ A physical motivation for a large mass splitting m_A0 - m_H0 ~ 200-300 GeV and the search for A0 -> Z H0 at LHC is provided: this large splitting leads to a strong EW phase transition in the early universe, which could be responsible for the generation of the observed matter-antimatter asymmetry via EW baryogenesis. It also analyzes LHC14 search prospects for A0 -> Z H0 in ll bb and ll W W (W -> l nu).
 +  * [[http://​​abs/​1404.1922]]:​ Detailed discussion of LHC14 search prospects for A0 -> Z H0 in both ll bb and ll Z Z, and H0 -> Z A0 in ll bb.
 +**__Constraints on 2HDM (e.g. Flavour)__**:​
 +  * [[http://​​abs/​1208.2788]] Bounds on m_H+ from b -> s gamma, both for Type I and Type II. They show that for Type II, the bound is particularly strong (m_H+ > 380 GeV) and tan_beta independent.
2015/groups/higgs/morehiggs/largesplit.txt · Last modified: 2015/06/18 18:09 by