New physics through interference of nonstandard interactions with Standard Model in rare decays of Bc+ meson

2018 ◽  
Vol 33 (30) ◽  
pp. 1850171
Author(s):  
Shakeel Mahmood ◽  
Farida Tahir ◽  
Azeem Mir
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Rare Decays ◽  
New Physics ◽  
Final State ◽  
Neutrino Interactions ◽  
Bc Meson ◽  
Free Parameters

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.

scholarly journals The effects of nonstandard neutrino interactions (NSIs) in KL0 → π0νν̄, B+ → π+νν̄, B+ → K∗+νν̄ and B → Xsνν̄

2015 ◽  
Vol 30 (25) ◽  
pp. 1550154 ◽  
Author(s):  
Shakeel Mahmood ◽  
Farida Tahir ◽  
Azeem Mir
Keyword(s):  
Standard Model ◽  
Rare Decays ◽  
Free Parameter ◽  
Strong Dependence ◽  
New Physics ◽  
Small Contribution ◽  
Third Generation ◽  
Dominant Contribution ◽  
Final State ◽  
Neutrino Interactions

We study the rare decays [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] for the search of NSIs. We want to constrain the NSIs by using these reactions. We show that there is a strong dependence of these reactions on new physics free parameter [Formula: see text], where [Formula: see text], [Formula: see text], [Formula: see text]. We include second and third generation of quarks in the loop for these decays. We show that the [Formula: see text] is providing very precise bounds as compared to all other semileptonic decays, having neutrinos in their final state. We further show that the interference between standard model and NSIs is giving dominant contribution for [Formula: see text], [Formula: see text] and [Formula: see text]. We point out that the constraints for [Formula: see text] and [Formula: see text] are more precise as compared to [Formula: see text]. The analysis of [Formula: see text], [Formula: see text] and [Formula: see text], provide us that the [Formula: see text]-quark induced Br of NSIs are giving very small contribution. We also compare these decays to the decays of charm and kaons having neutrinos in the final state.

scholarly journals THE DYNAMICAL MODELS AND THE $Z \rightarrow b\bar{b}$ ASYMMETRY

2002 ◽  
Vol 17 (05) ◽  
pp. 261-268 ◽  
Author(s):  
CHONGXING YUE ◽  
YUANBEN DAI ◽  
HONG LI
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
New Physics ◽  
Dynamical Models ◽  
Effective Lagrangian ◽  
The Standard Model ◽  
Free Parameters

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.

SEARCH FOR NEW PHYSICS IN eμX DATA AT THE TEVATRON USING SLEUTH: A QUASI-MODEL-INDEPENDENT SEARCH STRATEGY FOR NEW PHYSICS

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 888-890
Author(s):  
◽  
BRUCE KNUTESON
Keyword(s):  
Standard Model ◽  
Search Strategy ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Final States ◽  
Final State ◽  
The Standard Model ◽  
Model Independent

We present a quasi-model-independent search for physics beyond the standard model. We define final states to be studied, and construct a rule that identifies a set of variables appropriate for any particular final state. A new algorithm ("Sleuth") searches for regions of excess in the space of those variables and quantifies the significance of any detected excess. After demonstrating the sensititvity of the method, we apply it to the semi-inclusive channel eμX collected in ≈108 pb -1 of [Formula: see text] collisions at [Formula: see text] at the DØ experiment at the Fermilab Tevatron. We find no evidence of new high pT physics in this sample.

CAN WE RELATE TIME-REVERSAL VIOLATION TO NEW PHYSICS PROCESSES IN WEAK HADRONIC DECAYS?

2013 ◽  
Vol 22 (03) ◽  
pp. 1330006 ◽  
Author(s):  
Z. J. AJALTOUNI ◽  
E. DI SALVO
Keyword(s):  
Experimental Data ◽  
Cp Violation ◽  
Standard Model ◽  
Time Reversal ◽  
Review Paper ◽  
New Physics ◽  
Hadronic Decays ◽  
Beyond The Standard Model ◽  
Weak Decays ◽  
The Standard Model

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.

scholarly journals RARE DECAYS AND CP VIOLATION BEYOND THE STANDARD MODEL

2006 ◽  
Vol 21 (08n09) ◽  
pp. 1738-1749 ◽  
Author(s):  
LUCA SILVESTRINI
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Rare Decays ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Unitarity Triangle ◽  
Minimal Flavour Violation ◽  
The Standard Model ◽  
The Status ◽  
Flavour Violation

We review the status of rare decays and CP violation in extensions of the Standard Model. We analyze the determination of the unitarity triangle and the model-independent constraints on new physics that can be derived from this analysis. We find stringent bounds on new contributions to [Formula: see text] and [Formula: see text] mixing, pointing either to models of minimal flavour violation or to models with new sources of flavour and CP violation in b → s transitions. We discuss the status of the universal unitarity triangle in minimal flavour violation, and study rare decays in this class of models. We then turn to supersymmetric models with nontrivial mixing between second and third generation squarks, discuss the present constraints on this mixing and analyze the possible effects on CP violation in b → s nonleptonic decays and on [Formula: see text] mixing. We conclude presenting an outlook on Lepton-Photon 2009.

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
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
New Physics ◽  
The Other ◽  
Tree Amplitude ◽  
Systematic Method ◽  
Cp Asymmetry ◽  
Strong Phase ◽  
Weak Phase ◽  
Hadronic Parameter

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

scholarly journals Studies of Missing Energy Decays at Belle II

2018 ◽  
Vol 46 ◽  
pp. 1860072
Author(s):  
Yinghui Guan
Keyword(s):  
Standard Model ◽  
Rare Decays ◽  
Neutral Current ◽  
Beyond The Standard Model ◽  
Missing Energy ◽  
Final State ◽  
Full Reconstruction ◽  
The Standard Model ◽  
Belle Ii ◽  
The Spectator

The Belle II experiment at the SuperKEKB collider is a major upgrade of the KEK “B factory” facility in Tsukuba, Japan. The machine is designed for an instantaneous luminosity of [Formula: see text], and the experiment is expected to accumulate a data sample of about 50 ab[Formula: see text]. With this amount of data, decays sensitive to physics beyond the Standard Model can be studied with unprecedented precision. One promising set of modes are physics processes with missing energy such as [Formula: see text], [Formula: see text], and [Formula: see text] decays. The [Formula: see text] decay provides one of the cleanest experimental probes of the flavour-changing neutral current process [Formula: see text], which is sensitive to physics beyond the Standard Model. However, the missing energies of the neutrinos in the final state makes the measurement challenging and requires full reconstruction of the spectator [Formula: see text] meson in [Formula: see text] events. This report discusses the expected sensitivities of Belle II for these rare decays.

scholarly journals D * Polarization as an Additional Constraint on New Physics in the b → cτ ν ¯ τ Transition

Particles ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 193-207
Author(s):  
Mikhail A. Ivanov ◽  
Jürgen G. Körner ◽  
Pietro Santorelli ◽  
Chien-Thang Tran
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Branching Fractions ◽  
Experimental Studies ◽  
Form Factors ◽  
Unknown Origin ◽  
New Physics ◽  
Constituent Quark Model ◽  
Tensor Operator ◽  
The Standard Model

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 .

CHARM MIXING AND CP VIOLATION AT B-FACTORIES

2014 ◽  
Vol 35 ◽  
pp. 1460413
Author(s):  
GIANLUIGI CIBINETTO ◽  
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
New Physics ◽  
Ratio Analysis ◽  
Charm Meson ◽  
Final State ◽  
Charm Decays ◽  
Decay Modes ◽  
The Standard Model ◽  
Model Predictions

CP violation in charm decays is expected to be very small in the Standard Model, at the level of 0.1% or less. A sizable excess of CP violation with respect to the Standard Model predictions could be a signature of new physics. We report on recent searches for CP violation in charm meson decays at BABAR and Belle experiments. In particular we report a lifetime ratio analysis of D0 → K+K−, π+π− with respect to D0 → K−π+ decays, which is sensitive to [Formula: see text] mixing and CP violation. We report also on searches for CPV in the 3-body D+ → K+K−π+ decay and for decay modes with a [Formula: see text] in the final state, such as [Formula: see text].

scholarly journals B → K(∗)μ+μ− in covariant quark model

2015 ◽  
Vol 39 ◽  
pp. 1560113
Author(s):  
A. Liptaj ◽  
S. Dubnička ◽  
A. Z. Dubničková ◽  
M. A. Ivanov
Keyword(s):  
Beyond Standard Model ◽  
Standard Model ◽  
Quark Model ◽  
Rare Decays ◽  
Form Factors ◽  
New Physics ◽  
Angular Distributions ◽  
Heavy Mesons ◽  
Theoretical Predictions ◽  
Covariant Quark Model

The covariant quark model with infrared confinement (CQM) is a well-suited theoretical framework to describe large variety of hadronic processes, including rare decays of heavy mesons. In this text we focus on the reactions [Formula: see text], which have been recently measured by Refs. 1–4. The measurements include also information about the angular distributions and their significance is given by possible New Physics (NP) effects which are predicted in numerous beyond Standard Model (SM) scenarios. Even with clever choice of experimental observables, a model dependence cannot be fully removed from the theoretical predictions. In this text we present the computation of the [Formula: see text] form factors within the CQM and give results for some of the most commonly used observables ([Formula: see text], [Formula: see text]).

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