CHROMOMAGNETIC AND CHROMOELECTRIC DIPOLE MOMENTS OF THE TOP QUARK IN THE 4GTHDM

Transcription

1 CHROMOMAGNETIC AND CHROMOELECTRIC DIPOLE MOMENTS OF THE TOP QUARK IN THE 4GTHDM ALAN IGNACIO HERNÁNDEZ JUÁREZ, AGUSTÍN MOYOTL ACUAHUITL AND GILBERTO TAVARES VELASCO FCFM, BUAP XXXII REUNIÓN ANUAL DIVISIÓN DE PARTÍCULAS Y CAMPOS, SMF MAY 29,

2 INTRODUCTION Since is discovery in 1995 he op quark has played a special role in he sudy of he phenomenology of he sandard model (SM). The LHC is a op quark facory, hen he sudy of he new conribuions o he chromomagneic dipole momen (CMDM) and chromoelecric dipole momen (CEDM) of he op quark is a opic worh sudying as hey could be a he reach of experimenal measuremen in he near fuure. A nonzero CEDM is a clear evidence of CP violaion. CP violaion is necessary o explain he baryon asymmery of he universe (Sakharov s crieria).

3 INTRODUCTION In he SM, he complex phase of he CKM marix gives rise o CP violaion, bu i is sill no enough o explain he baryon asymmery. New sources of CP violaion beyond he SM are required. The CMDM and CEDM can be induced via he following Lagrangian L = g st a 2 a 2m µ G a µ T a 2 i µ 5 d G a µ, a d Where is he CMDM, while is he CEDM. q q

4 4GTHDM The 4GTHDM is a variaion of a THDM ype-ii which inroduces a fourh generaion of fermions. (PhysRevD ) A model wih a fourh generaion of SM-Like quarks was sudied in he pas (SM4). Unforunaely, he SM4 is no consisen wih he Higgs producion a he LHC. In he 4GTHDM he heoreical predicion for Higgs boson producion a he LHC remains unchanged.(physrevd )

5 4GTHDM The Yukawa Lagrangian of he quark secor can be wrien as follows: L Y = Q L 1F I I d d d + 2 F I d d d 1G Q L I I u u u + 2 G I u u u d R u R +H.c., ( b, b 0,, 0 )=(0,1,0,1): h We focus in he 4GTHDM-l, where gives masses o he fermions of he fourh family only, whereas gives masses o he remaining fermions. `

6 4GTHDM Flavor changing neural currens (FCNCs) in he 4GTHDM arise a he ree level in he scalar secor and in general can be wrien as h 0 H 0 L = c s c c g f q i S 2m ij + P ij 5 W + s c s s f U ij are enries of he new 4x4 CKM marix, while I q is he weak isospin. q j +H.c., Where i (j) run over up (down) quarks ype for h 0, H 0 and A 0, while for H ± runs over up (down) quarks. f S ij P ij m qi s c ij f + ij f ij m qi f c A 0 2iI q ( + 1 ) f ij c ij + f + ij f ij m qi f ij + f + ij H ± 2 p U ij(m dj m ui )+h ij 1 2 U ij(m dj + m ui ) h + ij

7 f ± ij = 1 2 m q i q ij ± m q j q 4GTHDM, wih for up (down) ji q = u (d) quarks. h ± ij = 1 2 ( + 1 u,d ij )(m u k u ki U kj ± m dk d kj U ik) are enries of he new complex 4x4 mixing marices. u,d ' u,d 2 1 u,d u,d u,d u,d 2 2 u,d C A,

8 CMDM AND CEDM IN THE 4GTHDM The CMDM and CEDM of he op quark arise hrough he generic Feynman diagram Q φ Q =, 0 h 0, H 0 and A 0 Q = b, b 0 H ± Where for, whereas for.

9 CMDM AND CEDM IN THE 4GTHDM The conribuions o CMDM and CEDM are 2 g f 2 a (m Q ) = 2r W 8 2 d (m Q ) = g 2 s g f 2 m 2r W S Q 2 F (r Q,r )+ P Q 2 F ( r Q,r ) 8 2 Im S Q P Q G(r Q,r ),, Where F (x, y) = G(x, y) =x Z 1 0 Z 1 0 dz dz (1 z) 2 (z + x) (1 z)(x 2 z)+zy 2, (1 z) 2 (1 z)(x 2 z)+zy 2, r a = m a /m, S ij = S ij /m, and P ij = P ij /m

10 CMDM AND CEDM IN THE 4GTHDM The equaion for CMDM conribuion can be reduced o SM conribuion a h0 SM = G F m 2 4 p 2 2 Z 1 0 dz (1 + z)(1 z)2 (1 z) 2 + zr 2 h 0 SM, We obain a h0 SM =

11 CMDM AND CEDM IN THE 4GTHDM In our numerical analysis he parameer space is aken as Parameer Value m GeV m GeV m GeV U b, U 0 b U 0 b, U b b 0, b 0.5, 0.05 (scenario I), b 0.05, 0.05 (scenario II) b 0,, b /2, /4, /4 (scenarios I and II)

12 CMDM AND CEDM IN THE 4GTHDM The new physics conribuion is given as follows a 4GTHDM = a 3rd + a 4h, Where a 3rd = a h0 (m )+ X a (m )+a H ± (m b ), =H 0,A 0 a 4h = X =h 0,H 0,A 0 a (m 0)+a H ± (m b 0). a h0 (m )=a h0 (m ) a h0 SM

13 CMDM AND CEDM IN THE 4GTHDM a 3 rd (I) a 4h (I) a a h a H a A a 3 rd (II) 3 a 4h (II) 10-3 a H ± a 3 rd, a 4h a δa 4 GTHDM m [GeV] m [GeV] 10-6

14 CMDM AND CEDM IN THE 4GTHDM m H ± [GeV] m H ± [GeV] m b' =300 GeV, b' = π m b' =300 GeV, b' = 3 2 π d H ± e cm d H ± e cm H d ± (m b ) (I) H d ± (m b ) (II) m H ± =600 GeV, b' = π 4 m H ± =600 GeV, b' = 3 2 π d H ± (m b' ) (I) d H ± e cm d H ± e cm d H ± (m b' ) (II) m b' [GeV] m b' [GeV]

15 CONCLUSIONS A fourh generaion of fermions is sill consisen wih he 125 GeV Higgs measured in 2012 in he framework of he 4GTHDM. New sources of CP violaion are required in order o explain baryon asymmery of he universe. We obain conribuions of order for he CMDM and order for he CEDM. The mos recen bound o he CEDM is e cm, so our resul is very close.(physrevd ) The fourh family gives a high conribuion o he CMDM and CEDM e cm

16 THANK YOU