Radiative B decay spectrum: DGE at NNLO

Andersen, Jeppe R.; Gardi, Einan

doi:10.1088/1126-6708/2007/01/029

Cited by 42 publications

(59 citation statements)

References 72 publications

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“…Using 605 fb −1 of data taken at the Υ(4S) and 68 fb −1 taken below the resonance, we obtain B(B → X s γ : E B γ > 1.7 GeV) = (3.31 ± 0.19 ± 0.37 ± 0.01) × 10 −4 , where the errors are statistical, systematic and due to the boost correction, respectively. This result is in agreement with the latest theoretical calculations [1,2,27]. The results can be used to place constraints on new physics [32] and determine SM parameters such as the b-quark mass [33].…”

supporting

confidence: 89%

“…The unfolding matrix, derived from signal MC, is calibrated to data using the results of a study of radiative di-muon events, which gave the ECL response in data and MC in an energy and acceptance range consistent with our analysis. We use five signal models: KN [24], BLNP [25,26], DGE [27], BBU [28] and GG [29]. Values of the parameters of the signal model used in the signal MC are derived from fits to the signal spectrum shown in Fig 4. The two error bars for each point show the statistical and the total error, including the systematic error which is correlated among the points.…”

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confidence: 99%

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Improved Measurement of Inclusive Radiative B-meson decays

Schümann¹,

Limosani²

2008

AIP Conference Proceedings

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We report a fully inclusive measurement of the flavor changing neutral current decay $B\to X_s\gamma$ in the energy range $1.7 \GeV\le E^\mathrm{c.m.s}_\gamma\le 2.8 \GeV$, covering 97% of the total spectrum, where c.m.s is the center of mass system. Using $605\ifb$ of data, we obtain in the rest frame of the $B$-meson ${\mathcal B}(B\to X_s\gamma : E^B_\gamma>1.7 \mathrm{GeV})= (3.31 \pm 0.19 \pm 0.37 \pm 0.01)\times 10^{-4}$, where the errors are statistical, systematic and from the boost correction needed to transform from the rest frame of the $\Upsilon(4S)$ (c.m.s) to that of the $B$-meson, respectively. We also measure the first and second moments of the photon energy spectrum as functions of various energy thresholds, which extend down to $1.7 \GeV$. The results are preliminary.Comment: 10 pages, 11 figure

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supporting

confidence: 89%

mentioning

confidence: 99%

Improved Measurement of Inclusive Radiative B-meson decays

Schümann¹,

Limosani²

2008

AIP Conference Proceedings

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“…Far away from the endpoint (E 0 = 1.6 GeV), the logarithmic and nonlogarithmic terms cancel; this kind of cancellation was already observed in Ref. [40]. Within the resummation of the cutoff-enhanced logarithms this feature leads to an overestimate of the O(α 3 s ) terms [39].…”

Section: The Inclusive Decayb → X Sd γmentioning

confidence: 54%

News on penguins

Hurth¹

2012

AIP Conference Proceedings

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Abstract. We summarize recent theoretical developments in the field of radiative and semileptonic penguin decays. 13.20.He, 12.38.Bx, 12.39.St. MZ-TH/11-32 PACS: AMBIGUITY OF THE NEW PHYSICS SCALEWithin the indirect search for New Physics (NP) there is a an ambiguity of the new physics scale. In the modelindependent approach using the effective electroweak hamiltonean, the contribution to one specific operator O i can be parametrized viawhere the first term represents the SM contribution at the electroweak scale M W and the second one the NP contribution with an unknown coupling C i SM and an unknown NP scale Λ NP . The radiative and semi-leptonic penguin modes, b → sγ and b → sℓ + ℓ − , are flavour changing neutral current (FCNC) processes and, thus, are highly sensitive for new degrees of freedom via virtual effects (for reviews, see [1,2,3]) The non-existence of large NP effects in flavour observables in general [4,5] implies the famous flavour problem, namely why FCNC are suppressed. Either the mass scale of the new degrees of freedom, Λ NP , is very high or the new flavourviolating couplings, C i NP , are small for (symmetry?) reasons that remain to be found. For example, assuming generic new flavour-violating couplings of O(1), the present data on K-K mixing implies a very high NP scale of order 10 3 -10 4 TeV depending on whether the new contributions enter at loop-or at tree-level. In contrast, theoretical considerations on the Higgs sector, which is responsible for the mass generation of the fundamental particles in the SM, call for NP at order 1 TeV. As a consequence, any NP below the 1 TeV scale must have a non-generic flavour structure. In addition, also the present electroweak data indicate a slightly higher NP scale, a data-driven problem known as little hierarchy problem.The present measurements of B decays, especially of FCNC processes, already significantly restrict the parameter space of NP models. In general such bounds from flavour physics are model-dependent, but often much stronger than the ones derived from other measurements. In any case, the indirect flavour information will be most valuable when the general nature and the mass scale of NP will be known. THE INCLUSIVE DECAYB → X s,d γPerturbative contributions: Among the rare decay modes, the inclusive decayB → X s γ is the most important one, because it is theoretically well-understood and at the same time it has been measured extensively at the B factories. While non-perturbative corrections to this decay mode are subleading and recently estimated to be well below 10% [6], perturbative QCD corrections are the most important corrections. Within a global effort, a perturbative QCD calculation to the next-to-next-to-leading-logarithmic order level (NNLL) has quite recently been performed and has led to the first NNLL prediction of theB → X s γ branching fraction [7] with a photon cut at E γ = 1.6GeV (including the error due to nonperturbative corrections):B(B → X s γ) NNLL = (3.15 ± 0.23) × 10 −4 .(2)

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“…Such an approach can be used to predict large logarithms of the form ln(E max − E cut ). These computations have also achieved NNLO accuracy [26] and incorporate Sudakov and renormalon resummation via dressed gluon exponentiation (DGE) [26,27]. The present NNLO estimate of 1 − T = 0.016 ± 0.003 pert [26,28] indicates a much thinner tail of the photon energy spectrum and a considerable smaller perturbative uncertainty than reported in [22].…”

Section: Pos(kaon)056mentioning

confidence: 73%

Rare K- (vs.) B-decays

Haisch¹

2008

Proceedings of Kaon International Conference — PoS(KAON)

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We present a concise review of the recent theoretical progress concerning the standard model calculations of the rare K L → π 0 νν,The current status and future of the model-independent analysis of rare K-and B-meson decays within constrained minimal-flavor-violation is also briefly discussed. KAON International Conference May 21-25 2007Laboratori Nazionali di Frascati dell'INFN, Rome, Italy * Speaker. † We thank the organizers for the pleasant and stimulating atmosphere they were able to create during "KAON'07".Private communications with Einan Gardi and Mikołaj Misiak concerningB → X s γ are acknowledged.

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Radiative B decay spectrum: DGE at NNLO

Cited by 42 publications

References 72 publications

Improved Measurement of Inclusive Radiative B-meson decays

Improved Measurement of Inclusive Radiative B-meson decays

News on penguins

Rare K- (vs.) B-decays

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