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2013:groups:np:paired_resonances [2013/06/18 14:55] lorenzo.basso |
2013:groups:np:paired_resonances [2013/06/19 00:07] lorenzo.basso |
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__Signatures__: ''jjjj'' (covered), ''tbjj'' (interesting), ''tbtb'' (hopeless?) | __Signatures__: ''jjjj'' (covered), ''tbjj'' (interesting), ''tbtb'' (hopeless?) | ||
- | Exemple reference: [...] | + | Example reference: [...] |
* Scalar SU(2) Singlets ''S ~ (1,Y)'' | * Scalar SU(2) Singlets ''S ~ (1,Y)'' | ||
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* Vector SU(2) Doublets ''D_\mu ~ (2,Y)'' | * Vector SU(2) Doublets ''D_\mu ~ (2,Y)'' | ||
- | Perhaps the most interesting case. | + | Perhaps the most interesting case. In order to allow for decays, Y=±1/2, therefore, the double consists of a charged state D^± and a complex neutral state D_0. However, tree-level couplings to fermions are __all__ forbidden by lepton and barion number conservation, since they have to include a fermion doublet and a fermion singlet. Decays can be now given either via mixing with SM gauge bosons or by direct coupling to fermions via higher order operators, generated at loop level or via the Higgs boson (breaking SU(2)_L). |
+ | |||
+ | //Need to list all possible operators// | ||
* Scalar SU(2) Doublets ''D ~ (2,Y)'' | * Scalar SU(2) Doublets ''D ~ (2,Y)'' | ||
+ | //To be filled// | ||
+ | |||
+ | |||
+ | * Vector SU(2) Triples ''T_\mu ~ (3,Y)'' | ||
+ | As for the vector singlet, to allow decays one needs ''Y=0,±1''. It is only possible to couple the triplet to SM doublet fermions such as ''g_Tq \bar{Q_L} T_\mu \gamma^\mu Q_L'' and ''g_Tl \bar{L_L} T_\mu \gamma^\mu L_L''. Such couplings are allowed only for ''Y = 0'', hence also the triplet is made of a charged state T^± and a real neutral state T_0. | ||
+ | |||
+ | Only allowed decays are | ||
+ | T^± → tb, jj, l^±\nu | ||
+ | T_0 → tt, bb, jj, l^±l^\mp, \nu\nu | ||
+ | with constraints ''BR(T_0->l^±l^\mp) = BR(T0->\nu\nu)'' and ''BR(T0->tt) = BR(T0->bb)''. However, dilepton searches probably constraint BR in leptons to be very small. | ||
+ | |||
+ | __Signatures__ ''T_0T_0->jjjj, ttjj, tttt, ttbb, bbbb'', ''T^±T^\mp->jjjj, tbjj, tbtb'', ''T_0T^±->jjjj, ttjj, tbjj, bbjj, tttb, tbbb'' (am I missing anything?) | ||
+ | |||
+ | Notice, the T_0T_0 case behaves exactly like the vector singlet case. However, here one can exploit the correlation with the charge state that must be present. | ||
+ | |||
+ | |||
+ | * Scalar SU(2) Triples ''D ~ (3,Y)'' | ||
//To be filled// | //To be filled// |