On new physics in ΔΓ d

Bobeth, Christoph; Haisch, Ulrich; Lenz, Alexander; Pecjak, Ben D.; Tetlalmatzi-Xolocotzi, Gilberto

doi:10.1007/jhep06(2014)040

Cited by 72 publications

(99 citation statements)

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“…An interesting feature of this new interpretation is that a large enhancement of ∆Γ d by new physics effects could explain the experimental value of the dimuon asymmetry, while huge enhancements of the semileptonic CP asymmetries are disfavoured by direct measurements, see next section. The investigation of (Bobeth et al, 2014) has further shown that enhancements of ∆Γ d by several hundred per cent are not excluded by any other experimental constraint -such an enhancement could bring the dimuon asymmetry in agreement with experiment. One possible enhancement mechanism would be e.g.…”

Section: We Get As New Standard Model Valuesmentioning

confidence: 95%

“…Another enhancement mechanism would be new physics effects in tree-level decays, which are typically neglected. Such studies were performed systematically in (Bobeth et al, 2015(Bobeth et al, , 2014Brod et al, 2015) and could also lead to sizable enhancements of ∆Γ d . Here a more precise measurement of ∆Γ d would of course be very helpful.…”

Section: We Get As New Standard Model Valuesmentioning

confidence: 99%

“…Due to the dramatically improved experimental precision, this possibility has, however, to be considered. Taking only experimental constraints into account and no bias from model building, first studies performed by (Bobeth et al, 2014), (Bobeth et al, 2015) and (Brod et al, 2015) find that the tree-level Wilson coefficients C 1 and C 2 can easily be affected by new effects of the order of 0.1. Such a deviation can sometimes have dramatic effects, e.g.…”

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confidence: 99%

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CP violation in the Bs0 system

2016

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We review experimental and theoretical studies of CP violation in the B 0 s system. Updated predictions for the mixing parameters of the B 0 s mesons expected in the Standard Model (SM) are given, namely the mass difference ∆M SM s = (18.3±2.7) ps −1 , the decay rate difference ∆Γ SM s = (0.085 ± 0.015) ps −1 , and the flavour specific CP asymmetry a s,SM fs = (2.22 ± 0.27) × 10 −5 and the equivalent quantities in the B 0 -sector. Current experimental values of ∆Ms and ∆Γs agree with remarkable precision with theoretical expectations. This agreement supports the applicability of theoretical tools such as the Heavy Quark Expansion (HQE) to these decays. CP violating studies in the B 0 s system provide essential information to test the SM expectations, and to unveil possible contribution of the new physics (NP). NP effects on ∆Ms of the order of 15% are still possible. The CP phase φs due to CP violation in interference of decays and mixing can accommodate effects of the order of O(100%). The semileptonic CP asymmetry a s sl due to CP violation in mixing could still be a factor of 130 larger than its robust SM expectation and thus provides a very clean observable for NP searches. Theoretical improvements that are necessary to make full use of the experimental precision are discussed.

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Section: We Get As New Standard Model Valuesmentioning

confidence: 95%

Section: We Get As New Standard Model Valuesmentioning

confidence: 99%

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CP violation in the Bs0 system

2016

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“…III), the absence of new-physics contributions to the tree-level Wilson coefficients of the SM current-current operators has, to our knowledge, hitherto not been questioned in this context. In this article we investigate the experimental bounds on new physics contributions to these Wilson coefficient by extending the set of observables considered in [7,8]. Assuming that the new-physics effects are flavor universal we find that, from a purely phenomenological viewpoint, we cannot exclude shifts in γ of the order of AE4°.…”

Section: Introductionmentioning

confidence: 99%

New physics effects in tree-level decays and the precision in the determination of the quark mixing angleγ

Brod

Lenz

Tetlalmatzi-Xolocotzi

et al. 2015

Phys. Rev. D

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(2015) 'New physics eects in tree-level decays and the precision in the determination of the quark mixing angle . ', Physical review D., 92 (3). 033002.Further information on publisher's website:http://dx.doi.org/10.1103/PhysRevD.92.033002Publisher's copyright statement:Reprinted with permission from the American Physical Society: Physical Review D 92, 033002 c 2015 by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We critically review the assumption that no new physics is acting in tree-level B-meson decays and study the consequences for the ultimate precision in the direct determination of the Cabibbo-KobayashiMaskawa (CKM) angle γ. In our exploratory study we find that sizeable universal new physics contributions, ΔC 1;2 , to the tree-level Wilson coefficients C 1;2 of the effective Hamiltonian describing weak decays of the b quark are currently not excluded by experimental data. In particular, we find that ImΔC 1 and ImΔC 2 can easily be of order AE10% without violating any constraints from data. Such a size of new physics effects in C 1 and C 2 corresponds to an intrinsic uncertainty in the CKM angle γ of the order of jδγj ≈ 4°, which is slightly below the current experimental precision. The accuracy in the determination of γ can be improved by putting stronger constraints on the tree-level Wilson coefficients, in particular C 1 . To this end we suggest a more refined theoretical study as well as more precise measurements of the observables that currently provide the strongest bounds on hypothetical new weak phases in C 1 and C 2 . We note that the semileptonic CP asymmetries seem to have the best prospect for improving the bound on the weak phase in C 1 .

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“…Performing constraints on the new Z ′ couplings through low-energy precise processes is, on the other hand, very crucial and complementary for these direct searches Z ′ → e + e − at the Tevatron [26]. It is interesting to note that such a family non-universal Z ′ model could bring new CP -violating phases beyond the SM and have a large effect on many FCNC processes [27,28], such as the B s −B s mixing [29][30][31][32][33], as well as some rare [34] and hadronic B−meson decays [35,36].…”

Section: Introductionmentioning

confidence: 99%

Effects of neutralZ′boson inBs→φℓ
Ahmed
¹
,
Aslam
²
,
Paracha
³

2014
Phys. Rev. D
5
0
1
0
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The effects of new neutral Z ′ boson in Bs → φℓ + ℓ − , when φ is longitudinal or transverse polarized, are studied. In addition, the implications of Z ′ boson on the unpolarized and polarized CP violation asymmetries, with reference to lepton, are also presented. It is observed that the branching ratio with polarized φ are quite sensitive to the Z ′ contributions which are coming through the modification of Wilson coefficients C ef f 9 and C10. Moreover, the off-diagonal elements of the chiral Z ′ couplings contain new weak phase φ sb that provide a new source of CP violation. Keeping in view that in the FCNC transitions the CP violation asymmetries are highly suppressed in the SM, we have studied the unpolarized and polarized CP violation asymmetries in Bs → φℓ + ℓ − decays. Our results indicate that these CP violation asymmetries are remarkably significant and can attribute the any new physics coming through the Z ′ boson. It is hoped that the accurate measurements of these asymmetries will not only help us to establish NP but will also give a chance to determine the precise values of the coupling parameters of the Z ′ boson. I. INTRODUCTIONThe purpose of high energy experiments is to resolve the unanswered questions in the Standard Model (SM) through searches of new physics (NP) using complimentary approaches. The first approach is at the energy frontiers where the key representatives are the ATLAS and CMS experiments at the Large Hadron Collider (LHC) at CERN. The main purpose of these two detectors is to smash the particles at sufficiently large energy and then study the different particles produced after this collision. The second approach is at the rare/precision frontier where LHCb experiment at the LHC and the Belle II at the super KEKB are the names of two important experiments in regard to the flavor physics.In the precision approach the observable signature of new particles or processes can be obtained through the measurements of flavor physics reactions at lower energies and collect the evidence of any deviation from these predictions. A natural place is to investigate the flavor-changing-neutral-current (FCNC) processes in B-meson decays where one of the heavy quark makes them an ideal laboratory to test the non-perturbative aspects of the QCD and also make them a fertile hunting ground for testing the SM and probing the possible NP effects.Undoubtedly, the predictions of the SM are in good agreement with the collider data until now, however, still there exists some mysteries that are unanswered in this model. Just to name the few, they include neutrino oscillations, baryon asymmetry, dark matter, unification, the strong CP violation and the hierarchy problems. To answer these issues there exists a plethora of the NP models such as the extra dimension models, various supersymmetric models, etc. In grand unification theories such as SU (5) or string-inspired E6 models [1][2][3][4][5], one of the most pertinent is the Z ′ scenarios that include the family non-universal Z ′ [6,7] and leptophobic Z ′ ...

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On new physics in ΔΓ d

Cited by 72 publications

References 65 publications

CP violation in the Bs0 system

CP violation in the Bs0 system

New physics effects in tree-level decays and the precision in the determination of the quark mixing angleγ

Effects of neutralZ′boson inBs→φℓ
Ahmed
¹
,
Aslam
²
,
Paracha
³

2014
Phys. Rev. D
5
0
1
0
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On new physics in ΔΓ d

Cited by 72 publications

References 65 publications

CP violation in the Bs0 system

CP violation in the Bs0 system

New physics effects in tree-level decays and the precision in the determination of the quark mixing angleγ

Effects of neutralZ′boson inBs→φℓAhmed1, Aslam2, Paracha3 2014Phys. Rev. D5010View full textAdd to dashboardCite

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Effects of neutralZ′boson inBs→φℓ
Ahmed
¹
,
Aslam
²
,
Paracha
³

2014
Phys. Rev. D
5
0
1
0
View full text Add to dashboard Cite