scholarly journals TRIPLE-PRODUCT CORRELATIONS IN B→V1V2 DECAYS AND NEW PHYSICS

2004 ◽  
Vol 19 (15) ◽  
pp. 2505-2544 ◽  
Author(s):  
ALAKABHA DATTA ◽  
DAVID LONDON
Keyword(s):  
State Vector ◽  
New Physics ◽  
Triple Product ◽  
Beyond The Standard Model ◽  
B Decays ◽  
Final State ◽  
Angular Analysis ◽  
The Standard Model ◽  
The Right ◽  
B Quark

In this paper we examine T-violating triple-product correlations (TP's) in B→V1V2 decays. TP's are excellent probes of physics beyond the standard model (SM) for two reasons: (i) within the SM, most TP's are expected to be tiny, and (ii) unlike direct CP asymmetries, TP's are not suppressed by the small strong phases which are expected in B decays. TP's are obtained via the angular analysis of B→V1V2. In a general analysis based on factorization, we demonstrate that the most promising decays for measuring TP's in the SM involve excited final-state vector mesons, and we provide estimates of such TP's. We find that there are only a handful of decays in which large TP's are possible, and the size of these TP's depends strongly on the size of nonfactorizable effects. We show that TP's which vanish in the SM can be very large in models with new physics. The measurement of a nonzero TP asymmetry in a decay where none is expected would specifically point to new physics involving large couplings to the right-handed b-quark.

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.

scholarly journals Charming loops in exclusive rare FCNC B-decays

2019 ◽  
Vol 222 ◽  
pp. 01007 ◽  
Author(s):  
Dmitri Melikhov
Keyword(s):  
Standard Model ◽  
Gain Control ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Reliable Control ◽  
B Decays ◽  
Flavour Changing Neutral Currents ◽  
Neutral Currents ◽  
The Standard Model ◽  
Theoretical Predictions

Rare B-decays induced by flavour-changing neutral currents (FCNC) is one of the promising candidates for probing physics beyond the Standard model. However, for identifying potential new physics from the data, reliable control over QCD contributions is necessary. We focus on one of such QCD contributions – the charming loops – that potentially can lead to difficulties in disentangling new physics effects from the observable and discuss the possibility to gain control over theoretical predictions for charming loops.

scholarly journals Signatures of New Physics Versus the Ridge Phenomenon in Hadron–Hadron Collisions at the LHC

Physics ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 84-91 ◽  
Author(s):  
Miguel-Angel Sanchis-Lozano ◽  
Edward K. Sarkisyan-Grinbaum
Keyword(s):  
Fourier Series ◽  
Large Hadron Collider ◽  
Fourier Analysis ◽  
Parton Shower ◽  
Hadron Collider ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Final State ◽  
Azimuthal Correlations ◽  
The Standard Model

In this paper, we consider the possibility that a new stage of matter stemming from hidden/dark sectors beyond the Standard Model, to be formed in p p collisions at the LHC (Large Hadron Collider), can significantly modify the correlations among final-state particles. In particular, two-particle azimuthal correlations are studied by means of a Fourier series sensitive to the near-side ridge effect while assuming that hidden/dark particles decay on top of the conventional parton shower. Then, new (fractional) harmonic terms should be included in the Fourier analysis of the azimuthal anisotropies, encoding the hypothetical new physics contribution and enabling its detection in a complementary way to other signatures.

scholarly journals Search for single production of vector-like B quark decaying to bZ at future linear colliders

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Lin Han ◽  
Jie-Fen Shen
Keyword(s):  
Linear Collider ◽  
Decay Channel ◽  
High Energy ◽  
New Physics ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Linear Colliders ◽  
Single Production ◽  
Model Independent ◽  
B Quark

AbstractNew vector-like quarks are predicted in many new physics scenarios beyond the Standard Model (SM). Based on a model-independent framework, we investigate the prospect of discovering the SU(2) singlet vector-like bottom quark (VLQ-B) in $$e^{+}e^{-}$$ e + e - collisions at 3 TeV Compact Linear Collider. We study the single VLQ-B production process $$e^{-}e^{+}\rightarrow B{\bar{b}}\rightarrow Zb{\bar{b}}$$ e - e + → B b ¯ → Z b b ¯ with two types of decay channel: $$Z\rightarrow \ell ^{+}\ell ^{-}$$ Z → ℓ + ℓ - , and $$Z\rightarrow \nu {\bar{\nu }}$$ Z → ν ν ¯ . By carrying out a full simulation for the signals and the relevant SM backgrounds, the $$2\sigma $$ 2 σ exclusion limit and $$5\sigma $$ 5 σ discovery prospects are, respectively, obtained on the B quark mass and the coupling strength $$g^{*}$$ g ∗ with the integrated luminosity of 5 $$\hbox {ab}^{-1}$$ ab - 1 . Our numerical results show that the possible signals of the singlet VLQ-B might be detected at the future high-energy $$e^{+}e^{-}$$ e + e - linear colliders.

scholarly journals Mapping out the space for new physics with leptonic and semileptonic $$B_{(c)}$$ decays

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Robert Fleischer ◽  
Ruben Jaarsma ◽  
Gilberto Tetlalmatzi-Xolocotzi
Keyword(s):  
New Physics ◽  
Tensor Operator ◽  
Beyond The Standard Model ◽  
Final State ◽  
Ckm Matrix ◽  
The Standard Model ◽  
The Individual ◽  
Pseudo Scalar ◽  
Additional Constraints ◽  
Lepton Flavour

AbstractDecays of B mesons with leptons in the final state offer an interesting laboratory to search for possible effects of physics from beyond the Standard Model. In view of puzzling patterns in experimental data, the violation of lepton flavour universality is an interesting option. We present a strategy, utilising ratios of leptonic and semileptonic B decays, where the elements $$|V_{ub}|$$ | V ub | and $$|V_{cb}|$$ | V cb | of the Cabibbo–Kobayashi–Maskawa (CKM) matrix cancel, to constrain the short-distance coefficients of (pseudo)-scalar, vector and tensor operator contributions. The individual branching ratios allow us then to extract also the CKM matrix elements, even in the presence of new-physics contributions. Bounds on unmeasured leptonic and semileptonic decays offer important additional constraints. In our comprehensive analysis, we give also predictions for decays which have not yet been measured in a variety of scenarios.

scholarly journals Polarization in (quasi-)two-body decays and new physics

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
Z. J. Ajaltouni ◽  
E. Di Salvo
Keyword(s):  
Time Reversal ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Covariant Formalism ◽  
Final State ◽  
Leptonic Decays ◽  
Weak Decays ◽  
The Standard Model ◽  
Final State Interactions ◽  
Major Attention

AbstractWe consider two-body and quasi-two-body decays of the type $$f_1 \rightarrow f_2 B$$f1→f2B, where $$f_1$$f1 and $$f_2$$f2 are spin-1/2 fermions and B a spin-0 or spin-1 boson. After recalling the non-covariant formalism for decay amplitudes, we derive the expression of the differential decay width and of the polarizations of the final spinning particles, both on- and off-shell. We find an intriguing geometrical interpretation of the results about the polarization. We also illustrate some methods for measuring the polarizations of the resonances and for optimizing data analysis. Then we propose applications to semi-leptonic weak decays, with a major attention to the T-odd component of the polarization; this may help to find, simultaneously, possible time-reversal violations and hints to physics beyond the standard model. We suggest also a CPT test. Last, we discuss some T-odd observables for the production process of $$f_1$$f1 and for the study of the strong final state interactions of non-leptonic decays.

scholarly journals LHC Signatures of Vector-Like Quarks

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Yasuhiro Okada ◽  
Luca Panizzi
Keyword(s):  
New Physics ◽  
Short Description ◽  
Current Status ◽  
Beyond The Standard Model ◽  
Final States ◽  
Final State ◽  
Mixing Parameters ◽  
The Standard Model ◽  
Model Independent

This work provides an overview on the current status of phenomenology and searches for heavy vector-like quarks, which are predicted in many models of new physics beyond the Standard Model. Searches at Tevatron and at the LHC, here listed and shortly described, have not found any evidence for new heavy fermionic states (either chiral or vector-like) and have therefore posed strong bounds on their masses: depending on specific assumptions on the interactions and on the observed final state, vector-like quarks with masses up to roughly 400–600 GeV have been excluded by all experiments. In order to be as simple and model independent as possible, the chosen framework for the phenomenological analysis is an effective model with the addition of a vector-like quark representation (singlet, doublet, or triplet underSU(2)L) which couples through Yukawa interactions with all SM families. The relevance of different observables for the determination of bounds on mixing parameters is then discussed and a complete overview of possible two body final states for every vector-like quark is provided, including their subsequent decay into SM particles. A list and short description of phenomenological analyses present in the literature are also provided for reference purposes.

scholarly journals Disentangling QCD and new physics in D → πℓ+ℓ−

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Aoife Bharucha ◽  
Diogo Boito ◽  
Cédric Méaux
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
Branching Ratios ◽  
New Physics ◽  
Operator Product ◽  
Beyond The Standard Model ◽  
Spectral Functions ◽  
The Standard Model ◽  
Model Independent ◽  
Weak Annihilation

Abstract In this paper we consider the decay D+ → π+ℓ+ℓ−, addressing in particular the resonance contributions as well as the relatively large contributions from the weak annihilation diagrams. For the weak annihilation diagrams we include known results from QCD factorisation at low q2 and at high q2, adapting the existing calculation for B decays in the Operator Product Expansion. The hadronic resonance contributions are obtained through a dispersion relation, modelling the spectral functions as towers of Regge-like resonances in each channel, as suggested by Shifman, imposing the partonic behaviour in the deep Euclidean. The parameters of the model are extracted using e+e− → (hadrons) and τ → (hadrons) + ντ data as well as the branching ratios for the resonant decays D+ → π+R(R → ℓ+ℓ−), with R = ρ, ω, and ϕ. We perform a thorough error analysis, and present our results for the Standard Model differential branching ratio as a function of q2. Focusing then on the observables FH and AFB, we consider the sensitivity of this channel to effects of physics beyond the Standard Model, both in a model independent way and for the case of leptoquarks.

scholarly journals NEW PHYSICS UPPER BOUND ON THE BRANCHING RATIO OF Bs → l+l-γ

2007 ◽  
Vol 22 (18) ◽  
pp. 1319-1328 ◽  
Author(s):  
ASHUTOSH KUMAR ALOK ◽  
S. UMA SANKAR
Keyword(s):  
Upper Bound ◽  
Axial Vector ◽  
Branching Ratio ◽  
New Physics ◽  
Large Contribution ◽  
Beyond The Standard Model ◽  
Standard Model Expectation ◽  
Model Expectation ◽  
The Standard Model ◽  
Large Enhancement

We consider the effect of new physics on the branching ratio of Bs → l+l-γ where l = e, μ. If the new physics is of the form scalar/pseudoscalar, then it makes no contribution to Bs → l+l-γ, unlike in the case of Bs → l+l-, where it can potentially make a very large contribution. If the new physics is in the form of vector/axial-vector operators, then the present data on B → (K, K*) l+l- does not allow a large enhancement for B(Bs → l+l- γ). If the new physics is in the form of tensor/pseudotensor operators, then the data on B → (K, K*) l+l- gives no useful constraint but the data on B → K* γ does. Here again, a large enhancement of B(Bs → l+l-γ), much beyond the Standard Model expectation, is not possible. Hence, we conclude that the present data on b → s transitions allow a large boost in B(Bs → l+l-) but not in B(Bs → l+l-γ).

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