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

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.

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.


2015 ◽  
Vol 30 (02) ◽  
pp. 1550013 ◽  
Author(s):  
Shakeel Mahmood ◽  
Farida Tahir ◽  
Azeem Mir

We study rare decays [Formula: see text], [Formula: see text] and [Formula: see text] in NSIs. We calculate the NSIs branching ratios of these decays. There is a strong dependence of these on new physics parameter. We include second and third generation of quarks in the loop for these decays. We show that these provide stringent constraints on [Formula: see text], where Q = u, c, t, and [Formula: see text], where q = d, s, b. It is also pointed out that [Formula: see text] for α, β = e, μ.


2001 ◽  
Vol 16 (supp01b) ◽  
pp. 888-890
Author(s):  
◽  
BRUCE KNUTESON

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.


2006 ◽  
Vol 21 (08n09) ◽  
pp. 1738-1749 ◽  
Author(s):  
LUCA SILVESTRINI

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.


2018 ◽  
Vol 46 ◽  
pp. 1860072
Author(s):  
Yinghui Guan

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.


2014 ◽  
Vol 35 ◽  
pp. 1460413
Author(s):  
GIANLUIGI CIBINETTO ◽  

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].


2015 ◽  
Vol 30 (01) ◽  
pp. 1550004 ◽  
Author(s):  
Shakeel Mahmood ◽  
Farida Tahir ◽  
Azeem Mir

We study rare decays [Formula: see text], [Formula: see text] and [Formula: see text] in NSIs. We calculate the NSIs branching ratios of these decays. There is a strong dependence of these on new physics parameter. They provide stringent constraints on [Formula: see text], [Formula: see text] and [Formula: see text] (α, β = e, μ).


2015 ◽  
Vol 39 ◽  
pp. 1560113
Author(s):  
A. Liptaj ◽  
S. Dubnička ◽  
A. Z. Dubničková ◽  
M. A. Ivanov

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]).


2007 ◽  
Vol 22 (30) ◽  
pp. 5433-5442
Author(s):  
R. J. BARLOW

New results on rare decays of B mesons and τ leptons are summarised. Measurement are generally in excellent agreement with the Standard Model predictions, the only exceptions being the polarisation of vector particles in B decays and the non-appearance of CP violation in B ± → K ±π0.


2012 ◽  
Vol 27 (27) ◽  
pp. 1230028 ◽  
Author(s):  
JOHANNES ALBRECHT

The current experimental status of the searches for the very rare decays [Formula: see text] and [Formula: see text] is discussed. These channels are highly sensitive to various extensions of the Standard Model, especially in the scalar and pseudoscalar sector. The recent, most sensitive measurements from the CDF, ATLAS, CMS and LHCb collaborations are discussed and the combined upper exclusion limit on the branching fractions determined by the LHC experiments is shown to be 4.2×10-9 for [Formula: see text] and 0.8×10-9 for [Formula: see text]. The implications of these tight bounds on a selected set of New Physics models is sketched.


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