Gettingβ−αwithout penguin contributions

Abstract

Oscillation effects in B 0 →K S D 0 and related processes are considered to determine ␦ϵ␤Ϫ␣ϩϭ2␤ ϩ␥. We suggest that D 0 decays to CP eigenstates used in concert with inclusive D 0 decays provide a powerful method for determining ␦ cleanly. The CP asymmetry is expected to be Շ40% for D 0 decays to non-CP eigenstates and Շ80% for decays to CP eigenstates. This method can lead to a fairly accurate determination of ␦ with O(10 8 Ϫ10 9 ) B mesons.The two asymmetric B factories have made remarkable progress in determining one of the angles (␤) of the unitarity triangle; the world average now stands at sin 2␤ WA ϭ0.78 Ϯ0.08 ͓1,2͔. This is in very good agreement with the expectations from the standard model ͑SM͒, sin 2␤ SM ϭ0.70 Ϯ0.10 ͓3͔. However, a considerable amount of theoretical input has to be used to deduce sin 2␤ SM and progress in reducing the theory error is likely to be rather slow. Thus, methods that determine the angles without the uncertainties of hadronic matrix elements are crucial in testing the Cabibbo-Kobayashi-Maskawa ͑CKM͒ paradigm ͓4͔ to an increasing degree of accuracy in an effort to search for CP-odd phase͑s͒ due to physics beyond the SM.In the SM, CP violation is controlled by only one CP-odd phase. Therefore, different decays which measure the same angle of the unitarity triangle ͑UT͒ may give inconsistent results if physics beyond the SM is present. Likewise another apparent failure of unitarity of the CKM matrix, such as the failure of the UT to close, would also indicate new physics. Beyond the phase ␤, the determinations of ␣ and ␥, therefore, provide key SM tests.Two extensively studied methods for determining ␣ already exist, via B→ ͓5͔ and B→ ͓6͔. In these approaches, in addition to some experimental difficulties, considerable theoretical input is essential as these modes receive large QCD-penguin as well as some electroweak penguin ͑EWP͒ contributions. While efforts at these methods should certainly continue, it is also very important that, in our drive towards precision, we develop methods that do not require theoretical assumptions and therefore have negligible theory error. The key point is that the effect of beyond the SM CP-odd phase͑s͒ on B-physics may be quite small so any residual theory error on the determined unitarity angles may mask the effect of new physics and thwart experimental searches ͓7͔.The processes we consider ͑e.g. B 0 →K S D 0 ) use interference between b→u and b→c tree graphs; no penguin contribution, strong or EW, is involved ͓8͔. Time dependent CP-asymmetry measurements in B 0 (B 0 )→K S D 0 will give the combination of the unitarity angles ␦ϵ␤Ϫ␣ϩ, independent of the unitarity of the CKM matrix. If, however, one assumes unitarity of the CKM matrix then one also has, ␦ ϭ2␤ϩ␥ ͓9͔. Given that ␤ is already well measured, this method is very effective in determining ␣ ''cleanly,'' i.e. without QCD complications. In addition, this method can also be used to simultaneously extract ␤, allowing a crucial check against the value of ␤ determined with the B →J/K S 0 appr...

Search for new physics at a super-B factory

“…To answer this it is of some use to see the pace of progress of the past several years. Table I shows how lattice calculations of matrix elements around 1995 [22] yielded (amongst other things) sin 2β ≈ 0.59 ± 0.20, whereas the corresponding error decreased to around ±0.10 around 2001 [19,20,21]. In addition to β, such calculations also now constrain γ(≈ 60 • ) with an error of around 10 • .…”

“…Although the β determination from B 0 → D 0 K 0 is not competitive [27] with the B → J/ψK 0 method, it is still useful as it provides a good check of the CKM-paradigm. Note, in particular, that for B ± and for B 0 these methods for extracting angles of the UT using decays to D 0 final states are very clean as they require no theoretical assumptions such as isospin [28].…”

“…Note, in particular, that for B ± and for B 0 these methods for extracting angles of the UT using decays to D 0 final states are very clean as they require no theoretical assumptions such as isospin [28].…”

“…Efforts to calculate several of the relevant matrix elements on the lattice, with increasing accuracy, have been underway for past many years. A central role is played by the following four inputs [19,20,21]:…”

Higgs bosons from top quark decays

“…As dimension-six tW bh verticies originate from terms of the form tW b(v + h) [25,29], the size of anomalous 4-point tW bh couplings are restricted to be small by the stringent limits on anomalous tW b couplings [28,30,[37][38][39][40]. Anomalous htc/u couplings are constrained to be small [12,[41][42][43].…”