Effective valence quark model and a possible dip in $d\, {\rm Br}(B\to K\ell\bar{\ell})/dq^2$

In rare B meson decays B → Kℓ+ℓ-, a possible contribution of ℓ+ℓ- emission via photon from the "spectator" quark q(q = u, d) in the B meson [Formula: see text] is investigated in addition to the conventional one [Formula: see text]. If such a contribution is sizable compared with the standard estimation of B → Kℓ+ℓ-, we will observe visible difference between dΓ(B0 → K0ℓ+ℓ-)/dq2 and dΓ(B+ → K+ℓ+ℓ-)/dq2 in q2 dependence [Formula: see text]. Besides, as a result of the interference between the conventional one and a new one, a dip appears in dΓ(B → Kℓ+ℓ-)/dq2 at a small region of q2. The interference effect in the B0 decay will also be observed differently from that in the B+ decay. The calculation is done based on a semiclassical approach, a valence quark model. In the present model, the photon emission from the spectator quark q, d → d+γ(u → u+γ) is independent of the b–s transition mechanism, and the characteristic results are due to a straightforward estimate of the quark propagator which cannot be incorporated into the factorization method. The model is not a valence quark "dominant" model, so that, for example, the valence quarks in the final state carry only 24% of the energy–momentum of the kaon.

Download Full-text

FORM FACTORS FOR B→πlν DECAY IN A MODEL CONSTRAINED BY CHIRAL SYMMETRY AND QUARK MODEL

International Journal of Modern Physics A ◽

10.1142/s0217751x02012326 ◽

2002 ◽

Vol 17 (32) ◽

pp. 4927-4938 ◽

Cited By ~ 6

Author(s):

RIAZUDDIN ◽

T. A. AL-AITHAN ◽

AMJAD HUSSAIN SHAH GILANI

Keyword(s):

Vector Meson ◽

Quark Model ◽

Chiral Symmetry ◽

B Meson ◽

Valence Quark ◽

Form Factors ◽

Pole Mass ◽

Equal Time ◽

Quark Contribution ◽

Momentum Transfer Range

The form factors for the B→π transition are evaluated in the entire momentum transfer range by using the constraints obtained in the framework combining the heavy quark expansion and chiral symmetry for light quarks and the quark model. In particular, we calculate the valence quark contribution and show that it together with the equal time commutator contribution give to the form factors a pole behavior with the heavy (B-meson in our case) mass as the pole mass. This is in addition to the usual vector meson B*-pole diagram for B→πlν in the above framework. We discuss the predictions in our model, which provide an estimate of |Vub|2.

Download Full-text

Spectra of Exclusive Semi-Leptonic Decays of B-Meson in the Covariant Oscillator Quark Model

Progress of Theoretical Physics ◽

10.1143/ptp.98.159 ◽

1997 ◽

Vol 98 (1) ◽

pp. 159-167 ◽

Cited By ~ 3

Author(s):

M. Ishida ◽

S. Ishida ◽

M. Oda

Keyword(s):

Quark Model ◽

B Meson ◽

Leptonic Decays

Download Full-text

FINAL STATE INTERACTIONS IN B → ππK AND $B\to K\overline{K}K$ DECAYS

International Journal of Modern Physics A ◽

10.1142/s0217751x07036038 ◽

2007 ◽

Vol 22 (02n03) ◽

pp. 645-648

Author(s):

L. LEŚNIAK ◽

R. KAMIŃSKI ◽

B. EL-BENNICH ◽

B. LOISEAU ◽

A. FURMAN

Keyword(s):

Experimental Data ◽

Theoretical Model ◽

Unitary Representation ◽

B Meson ◽

Final State ◽

B Meson Decays ◽

Meson Decays ◽

Neutral B Meson ◽

Final State Interactions

Analysis of charged and neutral B meson decays into π+π-K, K+K-K and [Formula: see text] is performed using a unitary representation of the ππ and [Formula: see text] final state interactions. Comparison of the theoretical model with the experimental data of the Belle and BaBar Collaborations indicates that charming penguin contributions are necessary to describe the B → f0(980) K and B → ρ(770)0 K decays.

Download Full-text

Study of excited quark propagator contributions in perturbative chiral quark model

Annals of Physics ◽

10.1016/j.aop.2017.11.006 ◽

2018 ◽

Vol 388 ◽

pp. 114-121 ◽

Cited By ~ 3

Author(s):

X.Y. Liu ◽

Z.J. Liu ◽

A. Limphirat ◽

K. Khosonthongkee ◽

Y. Yan

Keyword(s):

Quark Model ◽

Quark Propagator ◽

Chiral Quark Model

Download Full-text

Studies of Missing Energy Decays at Belle II

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194518600728 ◽

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.

Download Full-text

PAULI INTERFERENCE EFFECT, K− LIFETIME AND ∆I=1/2 RULE IN K→2π DECAYS

International Journal of Modern Physics A ◽

10.1142/s0217751x89001230 ◽

1989 ◽

Vol 04 (12) ◽

pp. 3033-3040

Author(s):

DONGSHENG DU

Keyword(s):

Decay Rate ◽

Quark Model ◽

Interference Effect ◽

Relativistic Effect ◽

Final State Interaction ◽

State Interaction ◽

Nonleptonic Decay ◽

Final State ◽

Bag Model ◽

Nonrelativistic Quark Model

We estimate the interference effect on K− nonleptonic decay rate in terms of nonrelativistic quark model and the relativistic bag model. The calculation shows that the interference effect is very important. But both models mentioned above fail to describe it correctly. This seems to show that the relativistic effect and the final state interaction between quarks are crucial.

Download Full-text

B0 → J/ψf2(1270) decay in QCD factorization

Canadian Journal of Physics ◽

10.1139/p2012-079 ◽

2012 ◽

Vol 90 (12) ◽

pp. 1201-1208 ◽

Cited By ~ 1

Author(s):

Mahboobeh Sayahi ◽

Hossein Mahraban

Keyword(s):

Experimental Data ◽

B Meson ◽

Factorization Method ◽

Branching Ratios ◽

Hadronic Decay ◽

Light Meson ◽

Qcd Factorization ◽

Effective Coefficients

In this paper, the hadronic decay B0 → J/ψf2(1270) has been analyzed using the “QCD factorization” method. The effective coefficients [Formula: see text] have been calculated for three helicity states (h = 0, +, –) which give three contributions of amplitude. We have assumed two scenarios for J/ψ. First, we have considered that J/ψ behaves as a light meson compared to the B meson and second, we have considered the mass of J/ψ in our calculations meaning that mJ/ψ/mb is held fixed. The branching ratios are calculated in these two scenarios and also in different energy scales (μ = mb, μ = mb/2, and μ = 2mb). The obtained results are in agreement with available experimental data for the second scenario and μ = 2mb.

Download Full-text

Sensitivity of future linear $$\hbox {e}^+\hbox {e}^-$$ colliders to processes of dark matter production with light mediator exchange

The European Physical Journal C ◽

10.1140/epjc/s10052-021-09758-6 ◽

2021 ◽

Vol 81 (10) ◽

Author(s):

Jan Kalinowski ◽

Wojciech Kotlarski ◽

Krzysztof Mȩkała ◽

Paweł Sopicki ◽

Aleksander Filip Żarnecki

Keyword(s):

Dark Matter ◽

Linear Collider ◽

Production Cross ◽

Photon Emission ◽

International Linear Collider ◽

High Energy ◽

Initial State ◽

Final State ◽

State Radiation ◽

Wide Range

AbstractAs any $$e^+e^-$$ e + e - scattering process can be accompanied by a hard photon emission from the initial state radiation, the analysis of the energy spectrum and angular distributions of those photons can be used to search for hard processes with an invisible final state. Thus high energy $$e^+e^-$$ e + e - colliders offer a unique possibility for the most general search of dark matter (DM) based on the mono-photon signature. We consider production of DM particles at the International Linear Collider (ILC) and Compact Linear Collider (CLIC) experiments via a light mediator exchange. Detector effects are taken into account within the Delphes fast simulation framework. Limits on the light DM production in a simplified model are set as a function of the mediator mass and width based on the expected two-dimensional distributions of the reconstructed mono-photon events. The experimental sensitivity is extracted in terms of the DM production cross section. Limits on the mediator couplings are then presented for a wide range of mediator masses and widths. For light mediators, for masses up to the centre-of-mass energy of the collider, coupling limits derived from the mono-photon analysis are more stringent than those expected from direct resonance searches in decay channels to SM particles.

Download Full-text