IS THERE ANY PUZZLE OF NEW PHYSICS IN B → Kπ DECAYS?

2008 ◽  
Vol 23 (21) ◽  
pp. 3296-3299 ◽  
Author(s):  
C. S. KIM ◽  
SECHUL OH ◽  
YEO WOONG YOON

Due to re-parametrization invariance of decay amplitudes, any single new physics (NP) amplitude arising through either the electro-weak penguin (EWP) or the color-suppressed tree amplitude can be embedded simultaneously into both the color-suppressed tree and the EWP contribution in B → Kπ decays. We present a systematic method to extract each standard model (SM)-like hadronic parameter as well as new physics parameters in analytic way, so that one can pinpoint them once experimental data are given. Using the currently available experimental data for B → Kπ modes, we find two possible analytic results: one showing the large SM-like color-suppressed tree contribution and the other showing the large SM-like EWP contribution. The magnitude of the NP amplitude and its weak phase are quite large. For instance, we find |PNP/P′| = 0.39 ± 0.13, φNP = 92° ± 15° and δNP = 7° ± 26°, which are the ratio of the NP-to-SM contribution, the weak and the strong phase of the NP amplitude, respectively. We also investigate the dependence of the NP contribution on the weak phase γ and the mixing induced CP asymmetry of B0 → KSπ0, respectively

2013 ◽  
Vol 22 (03) ◽  
pp. 1330006 ◽  
Author(s):  
Z. J. AJALTOUNI ◽  
E. DI SALVO

This review paper stresses the possible connection between time-reversal violation and new physics processes beyond the standard model. In particular, this violation is proposed as an alternative to CP violation in the search for such unkown processes. Emphasis is put on the weak decays of heavy hadrons, especially beauty ones. Specific methods for extracting useful parameters from experimental data are elaborated in order to test TR symmetry. These methods could be used successfully in the analysis of the LHC data.


2018 ◽  
Vol 33 (30) ◽  
pp. 1850171
Author(s):  
Shakeel Mahmood ◽  
Farida Tahir ◽  
Azeem Mir

We investigate the nonstandard neutrino interactions (NSI) in the rare decays of [Formula: see text] mesons involving neutrinos in the final state. It is suggested that the interference between Standard Model and nonstandard interaction can provide sizeable contribution. We calculate the limits on NSI free parameters ([Formula: see text], [Formula: see text]) and compare them with experimental data.


Particles ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 193-207
Author(s):  
Mikhail A. Ivanov ◽  
Jürgen G. Körner ◽  
Pietro Santorelli ◽  
Chien-Thang Tran

Measurements of the branching fractions of the semileptonic decays B → D ( * ) τ ν ¯ τ and B c → J / ψ τ ν ¯ τ systematically exceed the Standard Model predictions, pointing to possible signals of new physics that can violate lepton flavor universality. The unknown origin of new physics realized in these channels can be probed using a general effective Hamiltonian constructed from four-fermion operators and the corresponding Wilson coefficients. Previously, constraints on these Wilson coefficients were obtained mainly from the experimental data for the branching fractions. Meanwhile, polarization observables were only theoretically studied. The situation has changed with more experimental data having become available, particularly those regarding the polarization of the tau and the D * meson. In this study, we discuss the implications of the new data on the overall picture. We then include them in an updated fit of the Wilson coefficients using all hadronic form factors from our covariant constituent quark model. The use of our form factors provides an analysis independent of those in the literature. Several new-physics scenarios are studied with the corresponding theoretical predictions provided, which are useful for future experimental studies. In particular, we find that under the one-dominant-operator assumption, no operator survives at 1 σ . Moreover, the scalar operators O S L and O S R are ruled out at 2 σ if one uses the constraint B ( B c → τ ν τ ) ≤ 10 % , while the more relaxed constraint B ( B c → τ ν τ ) ≤ 30 % still allows these operators at 2 σ , but only minimally. The inclusion of the new data for the D * polarization fraction F L D * reduces the likelihood of the right-handed vector operator O V R and significantly constrains the tensor operator O T L . Specifically, the F L D * alone rules out O T L at 1 σ . Finally, we show that the longitudinal polarization P L τ of the tau in the decays B → D * τ ν ¯ τ and B c → J / ψ τ ν ¯ τ is extremely sensitive to the tensor operator. Within the 2 σ allowed region, the best-fit value T L = 0.04 + i 0.17 predicts P L τ ( D * ) = − 0.33 and P L τ ( J / ψ ) = − 0.34 , which are at about 33% larger than the Standard Model (SM) prediction P L τ ( D * ) = − 0.50 and P L τ ( J / ψ ) = − 0.51 .


1994 ◽  
Vol 09 (40) ◽  
pp. 3741-3748
Author(s):  
RATHIN ADHIKARI ◽  
BISWARUP MUKHOPADHYAYA

If massive invisible particles are pair-produced in a three-body decay, the energy distribution of the other (visible) product will be sensitive to the mass of the invisible pair. We discuss the implications of this fact in the contexts of a Higgs boson decaying into (i) a Z-boson and two massive neutrinos of a fourth generation, and (ii) a Z and two lightest supersymmetric particles in the minimal supersymmetric standard model.


2002 ◽  
Vol 17 (05) ◽  
pp. 261-268 ◽  
Author(s):  
CHONGXING YUE ◽  
YUANBEN DAI ◽  
HONG LI

Motivated by the 3.2σ(1.4σ) deviations between the recent experimental value for [Formula: see text] and the standard model (SM) prediction, we examine the effect of new physics (NP) on the [Formula: see text] couplings [Formula: see text] and [Formula: see text]. First we focus our attention on the dynamical models. Then, using effective Lagrangian techniques, we discuss the corrections of NP to [Formula: see text] and [Formula: see text]. We find some kinds of NP which might explain the recently experimental data about Rb and [Formula: see text]. However, the free parameters of these kinds of NP must be severely constrained.


2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Damir Bečirević ◽  
Svjetlana Fajfer ◽  
Nejc Košnik ◽  
Aleks Smolkovič

AbstractWe show that the current values of $$R_K^\mathrm {exp}$$ R K exp and $$R_{K^*}^\mathrm {exp}$$ R K ∗ exp can be accommodated by allowing a nonzero New Physics coupling $$\delta C_9^{\mu \mu }$$ δ C 9 μ μ to be complex, both in the scenario in which only $$\delta C_9^{\mu \mu }$$ δ C 9 μ μ is affected, and in the scenario with complex $$\delta C_{9,10}^{\mu \mu }$$ δ C 9 , 10 μ μ satisfying $$\delta C_{9}^{\mu \mu }=-\delta C_{10}^{\mu \mu }$$ δ C 9 μ μ = - δ C 10 μ μ . A presence of the weak CP-violating phase can then be tested by measuring the CP-asymmetry, $$\mathcal {A}_\mathrm {CP}$$ A CP . We show that this asymmetry is enhanced around the peak of each $$c\bar{c}$$ c c ¯ -resonance, and in fact more pronounced in the close vicinity of $$J/\psi $$ J / ψ and $$\psi (2S)$$ ψ ( 2 S ) . Therefore, measuring $$\mathcal {A}_\mathrm {CP}$$ A CP before and after the resonances’ peak could be revelatory of the CP-violation that originates from beyond the Standard Model, or to be a significant constrain when building a realistic scenario of New Physics.


2009 ◽  
Vol 24 (supp01) ◽  
pp. 3-7 ◽  
Author(s):  
Jian-Ping Ma

The Standard Model (SM) has been successful at describing all relevant experimental phenomena and, thus, has been generally accepted as the fundamental theory of elementary particle physics. Despite its success, the SM leaves many unanswered questions. These can be classified into two main categories: one for subjects related to possible new physics at unexplored energy scales and the other for nonperturbertive physics, mostly related to Quantum Chromodynamics…


2014 ◽  
Vol 29 (38) ◽  
pp. 1450196 ◽  
Author(s):  
Hai-Bin Zhang ◽  
Guo-Hui Luo ◽  
Tai-Fu Feng ◽  
Shu-Min Zhao ◽  
Tie-Jun Gao ◽  
...  

The μνSSM, one of supersymmetric extensions beyond the Standard Model, introduces three singlet right-handed neutrino superfields to solve the μ problem and can generate three tiny Majorana neutrino masses through the seesaw mechanism. In this paper, we investigate the rare decay process [Formula: see text] in the μνSSM, under a minimal flavor violating assumption for the soft breaking terms. Constrained by the SM-like Higgs with mass around 125 GeV, the numerical results show that the new physics can fit the experimental data for [Formula: see text] and further constrain the parameter space.


1991 ◽  
Vol 06 (08) ◽  
pp. 1253-1266 ◽  
Author(s):  
CLAUDIO O. DIB ◽  
DAVID LONDON ◽  
YOSEF NIR

Of the many ingredients of the Standard Model that are relevant to the analysis of CP asymmetries in B0 decays, some are likely to hold even beyond the Standard Model while others are sensitive to new physics. Consequently, certain predictions are maintained while others may show dramatic deviations from the Standard Model. Many classes of models may show clear signatures when the asymmetries are measured: four quark generations, Z-mediated flavor-changing neutral currents, supersymmetry and “real superweak” models. On the other hand, models of left-right symmetry and multi-Higgs sectors with natural flavor conservation are unlikely to modify the Standard Model predictions.


2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Nico Adolph ◽  
Gudrun Hiller

Abstract We compute 10 radiative three-body decays of charged charmed mesons $$ {D}^{+}\to {P}_1^{+}{P}_2^0\gamma $$ D + → P 1 + P 2 0 γ and $$ {D}_s\to {P}_1^{+}{P}_2^0\gamma $$ D s → P 1 + P 2 0 γ , P1,2 = π, K, in leading order QCDF, HHχPT and the soft photon approximation. We work out decay distributions and asymmetries in the standard model and with new physics in the electromagnetic dipole operators. The forward-backward asymmetry is suitable to probe the QCD frameworks, in particular the s-channel dependent weak annihilation contributions in QCDF against the markedly different resonance structure in HHχPT. These studies can be performed with Cabibbo-favored modes Ds → π+π0γ, $$ {D}^{+}\to {\pi}^{+}{\overline{K}}^0\gamma $$ D + → π + K ¯ 0 γ and $$ {D}_s\to {K}^{+}{\overline{K}}^0\gamma $$ D s → K + K ¯ 0 γ with $$ \mathcal{O}\left({10}^{-4}-{10}^{-3}\right)\hbox{-} \mathrm{level} $$ O 10 − 4 − 10 − 3 ‐ level branching ratio, which are standard model-like and induced by different hadronic dynamics. Understanding of the latter can therefore be improved in a data-driven way and sharpens the interpretation of standard model tests. Singly Cabibbo-suppressed modes such as D+ → π+π0γ, Ds → π+K0γ, Ds → K+π0γ with branching ratios within ∼ 10−5–10−4 are sensitive to new physics that can be signalled in the forward-backward asymmetry and in the CP-asymmetry of the rate, ideally in the Dalitz region but also in single differential distributions. Results complement those with neutral D0→ P1P2γ decays.


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