The fourth family: A simple explanation for the observed pattern of anomalies in B–CPB–CP asymmetries

Soni, Anjan Kumar and Alok, A K and Giri, A and Mohanta, R and Nandi, S (2010) The fourth family: A simple explanation for the observed pattern of anomalies in B–CPB–CP asymmetries. Physics Letters B, 683 (4-5). pp. 302-305. ISSN 0370-2693

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We show that a fourth family of quarks with mt′mt′ in the range of (400–600) GeV provides a rather simple explanation for the several indications of new physics that have been observed involving CP asymmetries of the b -quark. The built-in hierarchy of the 4×44×4 mixing matrix is such that the t′t′ readily provides a needed perturbation (≈15%≈15%) to sin2βsin2β as measured in B→ψKsB→ψKs and simultaneously is the dominant source of CP asymmetry in Bs→ψϕBs→ψϕ. The correlation between CP asymmetries in Bs→ψϕBs→ψϕ and Bd→ϕKsBd→ϕKs suggests mt′≈(400–600) GeVmt′≈(400–600) GeV. Such heavy masses point to the tantalizing possibility that the 4th family plays an important role in the electroweak symmetry breaking. The spectacular performance of the two asymmetric B-factories allowed us to reach an important milestone in our understanding of CP-violation phenomena. For the first time it was established that the observed CP-violation in the B and K systems was indeed accountable by the single, CP-odd, Kobayashi–Maskawa phase in the CKM matrix [1] and [2]. In particular, the time dependent CP -asymmetry in the gold-plated B0→ψKsB0→ψKs can be accounted for by the Standard Model (SM) CKM-paradigm to an accuracy of around 15% [3] and [4]. It has then become clear that the effects of a beyond the standard model (BSM) phase can only be a perturbation. Nevertheless, in the past few years as more data were accumulated and also as the accuracy in some theoretical calculations was improved it has become increasingly apparent that several of the experimental results are difficult to reconcile within the SM with three generations [SM3] [5] and [6]. It is clearly important to follow these indications and to try to identify the possible origin of these discrepancies especially since they may provide experimental signals for the LHC which is set to start quite soon. While at this stage many extensions of the SM could be responsible, in this Letter, we will make the case that an addition of a fourth family of quarks [7], [8], [9], [10] and [11] provides a rather simple explanation for the pattern of deviations that have been observed [12]. In fact we will show that the data suggests that the charge 2/3 quark of this family needs to have a mass in the range of (400–600) GeV [13].

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Giri, Anjan KumarUNSPECIFIED
Item Type: Article
Additional Information: We thank Graham Kribs, Ulrich Nierste and Marc Sher for discussions. The work of A.S. is supported in part by the US DOE contract No. DE-AC02-98CH10886. This research grew as a part of a working group on flavor physics at the Xth Workshop of High Energy Physics Phenomenology (WHEPP X), Chennai, India (Jan 08). A.S. is grateful to organizers especially to Rahul Basu and Anirban Kundu for the invitation. The work of R.M. is supported by DST and A.G. by CSIR, Government of India. S.N.'s work is supported in part by MIUR under contact 2004021808-009 and by a European Community's contract MRTN-CT-2006-035505.
Subjects: Physics
Divisions: Department of Physics
Depositing User: Team Library
Date Deposited: 09 Sep 2015 05:06
Last Modified: 11 Sep 2017 10:23
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