Effects of Superheavy Quarks and Leptons in Low-Energy Weak Processes KL-&gt; Formula, K+-&gt; + Formula and K0 Formula

Inami, Takeo; Lim, Chapman

doi:10.1143/ptp.65.1772

Cited by 458 publications

(348 citation statements)

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“…As is well known [31], low energy effective lagrangians continue to provide the most useful description. In the following, we consider three examples of NP models with loop amplitudes.…”

Section: Np Models With Loop Amplitudesmentioning

confidence: 99%

RelatingD0−D¯0mixing andD0→l+
Golowich
¹
,
Hewett
²
,
Pakvasa
³

et al. 2009
Phys. Rev. D
97
11
86
0
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“…As is well known [31], low energy effective lagrangians continue to provide the most useful description. In the following, we consider three examples of NP models with loop amplitudes.…”

Section: Np Models With Loop Amplitudesmentioning

confidence: 99%

RelatingD0−D¯0mixing andD0→l+
Golowich
¹
,
Hewett
²
,
Pakvasa
³

et al. 2009
Phys. Rev. D
97
11
86
0
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“…In the SM, B → X s νν proceeds via W box and Z penguin diagrams, therefore only O L is present and η = 0. The corresponding coefficient reads [13] …”

Section: The B → X S νν Decay Ratementioning

confidence: 99%

First limit on inclusive decay and constraints on new physics

1996

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In a recent article [1] we presented the derivation of the first limit on the inclusive B → X s νν decay rate. Our work stemmed from the observation that a published ALEPH bound on BR(B → τν) [2], inferred from the absence of large missing energy events in B decays, implies also a limit on BR(B → X s νν). We estimated this limit by comparing the missing energy spectra in the two decay modes. Theoretically, B → X s νν is a very clean process, which is also sensitive to several possible sources of new physics [1]. Therefore, a dedicated experimental search is important. The result of such an analysis by the ALEPH Collaboration, using the full LEP-I data sample, is to appear soon [3].As a result of discussions with members of the ALEPH Collaboration [4], we found two errors in our numerical results. The corrected analysis yields a limit weaker than our original result [1] by about a factor of three. The corrections included here are formally beyond the free quark decay result at tree level (of order α s , Λ QCD /m b , and higher). However, they affect the final limit significantly, due to the specific details of the experimental analysis.First, due to a mistake in our Monte Carlo code, the energy of the X s hadronic final state in the B rest frame was evaluated as a fraction of the b quark mass, rather than as a fraction of the B meson mass. This resulted in a harder missing energy spectrum than the true one. Correcting for this weakens the limit by about 35%.Second, we neglected the effects of the invariant mass distribution of the final hadrons, 1 which we (implicitly) assumed not to extend to high mass states. However, the invariant mass of the X s system can be well above 1 GeV [5]. Because of the large boost into the LEP laboratory frame and the high missing energy range (> 35 GeV) used in the analysis[2] (which is large compared to the average B meson energy at LEP), neglecting this effect yielded a missing energy spectrum in the laboratory frame considerably harder than the correct one.It is not straightforward to include properly this second effect into the analysis. However, an estimate can be obtained by approximating the invariant mass spectrum of the X s system with a Gaussian distribution with mean (µ) and variance (σ) fitted to the averages M 2 X and M 4 X , as given in [5]. Such a fit yields µ ≃ 1.35 GeV and σ ≃ 0.6 GeV. There is about a 10% uncertainty in these values, due to their dependences on the heavy quark effective theory parameterΛ (≃ m B − m b ). Treating the X s mass distribution as independent of the energy spectrum, and including a theoretical uncertainty of about 15% related to the fitted values of µ and σ, we find that the original limit given in [1] is weakened by about a factor of three. While small values of E X favor small values of M X (beyond the trivial kinematic constraint E X > M X ), the correlation between E X and M X only slightly improve the bound.In conclusion, the bound on BR(B → X s νν) given in the Abstract and in Eqs. (1.2) and (6.1) of [1] is weaker by about a facto...

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“…In Eq. (1), both the Inami-Lim function S 0 (x t ) (x t = m 2 t /m 2 W ) [2] and the QCD coefficient η B can be calculated perturbatively.M Bq is a renormalization group invariant (RGI) ∆B = 2 four-fermion operator matrix element in an effective Hamiltonian of the box diagram at low-energy scale. The mixing matrix elementM Bq is a highly nonperturbative quantity, thus currently the only possible method for a precise determination is via numerical lattice QCD simulations.…”

Section: Introductionmentioning

confidence: 99%

NeutralBmeson mixings andBmeson decay constants with static heavy and domain-wall light quarks

et al. 2015

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Neutral B meson mixing matrix elements and B meson decay constants are calculated. Static approximation is used for b quark and domain-wall fermion formalism is employed for light quarks. The calculations are carried out on 2 + 1 flavor dynamical ensembles generated by RBC/UKQCD Collaborations with lattice spacings 0.086 fm (a −1 ∼ 2.3 GeV) and 0.11 fm (1.7 GeV), and a fixed physical spatial volume of about (2.7 fm) 3 . In the static quark action, link-smearings are used to improve the signal-to-noise ratio. We employ two kinds of link-smearings, HYP1 and HYP2, and their results are combined in taking the continuum limit. For the matching between the lattice and the continuum theory, one-loop perturbative O(a) improvements are made to reduce discretization errors. As the most important quantity of this work, we obtain SU (3)

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Effects of Superheavy Quarks and Leptons in Low-Energy Weak Processes KL-> Formula, K+-> + Formula and K0 Formula

Cited by 458 publications

References 0 publications

RelatingD0−D¯0mixing andD0→l+
Golowich
¹
,
Hewett
²
,
Pakvasa
³

et al. 2009
Phys. Rev. D
97
11
86
0
View full text Add to dashboard Cite

RelatingD0−D¯0mixing andD0→l+
Golowich
¹
,
Hewett
²
,
Pakvasa
³

et al. 2009
Phys. Rev. D
97
11
86
0
View full text Add to dashboard Cite

First limit on inclusive decay and constraints on new physics

NeutralBmeson mixings andBmeson decay constants with static heavy and domain-wall light quarks

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Effects of Superheavy Quarks and Leptons in Low-Energy Weak Processes KL-> Formula, K+-> + Formula and K0 Formula

Cited by 458 publications

References 0 publications

RelatingD0−D¯0mixing andD0→l+Golowich1, Hewett2, Pakvasa3 et al. 2009Phys. Rev. D9711860View full textAdd to dashboardCite

RelatingD0−D¯0mixing andD0→l+Golowich1, Hewett2, Pakvasa3 et al. 2009Phys. Rev. D9711860View full textAdd to dashboardCite

First limit on inclusive decay and constraints on new physics

NeutralBmeson mixings andBmeson decay constants with static heavy and domain-wall light quarks

Contact Info

Product

Resources

About

RelatingD0−D¯0mixing andD0→l+
Golowich
¹
,
Hewett
²
,
Pakvasa
³

et al. 2009
Phys. Rev. D
97
11
86
0
View full text Add to dashboard Cite

RelatingD0−D¯0mixing andD0→l+
Golowich
¹
,
Hewett
²
,
Pakvasa
³

et al. 2009
Phys. Rev. D
97
11
86
0
View full text Add to dashboard Cite