arXiv subjects

Manmohan Gupta

Publications and source records attributed to Manmohan Gupta.

60 records · Page 4Linked to original sources

arXiv2001

Chiral Quark Model with Configuration Mixing

The implications of one gluon exchange generated configuration mixing in the Chiral Quark Model ($χ$QM$_{gcm}$) with SU(3) and axial U(1) symmetry breakings are discussed in the context of proton flavor and spin structure as well as the hyperon $β$-decay parameters. We find that $χ$QM$_{gcm}$ with SU(3) symmetry breaking is able to give a satisfactory unified fit for spin and quark distribution functions, with the symmetry breaking parameters $α=.4$, $β=.7$ and the mixing angle $ϕ=20^o$, both for NMC and the most recent E866 data. In particular, the agreement with data, in the case of $G_A/G_V, Δ_8$, F, D, $f_s$ and $f_3/f_8$, is quite striking.

hep-ph↗

arXiv2001

Constructing "Reference" Triangle through Unitarity of CKM Matrix

Motivated by the possibility of the low value of sin2βin the measurements of BABAR and BELLE collaborations, a reference unitarity triangle is constructed using the unitarity of the CKM matrix and the experimental values of the well known CKM elements, without involving any inputs from the processes which might include the new physics effects. The angles of the triangle are evaluated by finding the CP violating phase δthrough the Jarlskog's rephasing invariant parameter J. The present data and the unitarity of the CKM matrix gives for δthe range 28^o to 152^o, which for sin2βtranslates to the range 0.21 to 0.88. This range is broadly in agreement with the recent BABAR and BELLE results. However, a value of sin2β\leq 0.2, advocated by Silva and Wolfenstein as a benchmark for new physics, would imply a violation in the three generation unitarity and would hint towards the existence of a fourth generation Further, the future refinements in the CKM elements will push the lower limit on sin2βstill higher.

hep-ph↗

arXiv2001

Texture Specific Mass Matrices and CP violating asymmetry in B^o_d({\bar B}^o_d) -> ψK_S

In the context of texture 4 - zero and texture 5 - zero hierarchical quark mass matrices, CP violating asymmetry in $B^o_d({\bar B}^o_d) \to ψK_S$ (sin2$β$) has been evaluated by considering quark masses at $m_Z$ scale. For a particular viable texture 4 - zero mass matrix the range of sin2βis: 0.27 - 0.60 and for the corresponding texture 5 - zero case it is 0.31 - 0.59. Further our calculations reveal a crucial dependence of sin2$β$ on light quark masses as well as the phase in this sector.

hep-ph↗

arXiv2000

Reconciling $G_A/G_V, $ and $μ_{p,n}$ in Chiral Quark Model with one Gluon Generated Configuration Mixing

The spin polarization functions $(Δu, ~Δd, ~Δs)$ for proton are calculated in the chiral quark model ($χ$QM) with SU(3) symmetry breaking as well as configuration mixing generated by one gluon exchange forces for the NMC and the most recent E866 data. Besides reproducing the spin polarization functions $Δu,Δd, Δs$ as well as $G_A/G_V$, it can accomodate nucleon magnetic moments and neutron charge radius as well, thus resolving the compatibility problem of these parameters which could not be achieved in constituent quark models.

hep-ph↗

arXiv2000

Implications of Configuration Mixing in The Chiral Quark Model With SU(3) and Axial U(1) Breakings for Nucleon Spin-Flavor Structure

The implications of Chiral Quark Model with SU(3) and axial U(1) symmetry breakings as well as configuration mixing generated by one gluon exchange forces ($χ$QM$_{gcm}$) are discussed in context of proton flavor and spin structure as well as hyperon $β$-decay data. Apart from reproducing the success of $χ$QM with symmetry breaking, it is able to improve upon the agreement with data in several cases such as, $G_A/G_V, Δ_8, $ dependent on spin polarization functions and ($\frac{2 \bar s}{u+d}$), ($\frac{2 \bar s}{\bar u+\bar d}$) and f_s involving the quark distribution functions.

hep-ph↗

arXiv1997

Fritzsch-Xing mass matrices, $V_{td}$ and CP Violating phase $δ$

Natural 4 zeros texture mass matrices recently proposed by Fritzsch and Xing have been investigated by including `non-leading'corrections in the context of latest data regarding m_t^{pole} and V_{CKM} matrix elements. Apart from accommodating m_t^{pole} in the range 175\pm15 GeV, |V_{cb}| and |V_{ub}/V_{cb}|=0.08\pm0.02, the analysis with maximal CP-violation predicts |V_{td}| = .005-.013. Further, the CP-violating phase angle δcan be restricted to the ranges (i) 22^o -45^o and (ii) 95^o - 130^o, concretizing the ambiguity regarding phase of CKM matrix. Furthermore, we find that non-leading calculations are important when `Cabibbo triangle' is to be linked to unitarity triangle.

hep-ph↗