scholarly journals BOUNDS ON QUARK MASS MATRICES ELEMENTS DUE TO MEASURED PROPERTIES OF THE MIXING MATRIX AND PRESENT VALUES OF THE QUARK MASSES

2008 ◽  
Vol 23 (11) ◽  
pp. 1729-1746 ◽  
Author(s):  
S. CHATURVEDI ◽  
V. GUPTA ◽  
G. SÁNCHEZ-COLÓN

We obtain constraints on possible structures of mass matrices in the quark sector by using as experimental restrictions the determined values of the quark masses at the MZ energy scale, the magnitudes of the quark mixing matrix elements V ud , V us , V cd and V cs , and the Jarlskog invariant J(V). Different cases of specific mass matrices are examined in detail. The quality of the fits for the Fritzsch- and Stech-type mass matrices is about the same with χ2/ d.o.f. = 4.23/3 = 1.41 and χ2/ d.o.f. = 9.10/4 = 2.28, respectively. The fit for a simple generalization (one extra parameter) of the Fritzsch type matrices, in the physical basis, is much better with χ2/ d.o.f. = 1.89/4 = 0.47. For comparison we also include the results using the quark masses at the 2 GeV energy scale. The fits obtained at this energy scale are similar to that at MZ energy scale, implying that our results are unaffected by the evolution of the quark masses from 2 to 91 GeV.

2007 ◽  
Vol 22 (32) ◽  
pp. 2463-2470 ◽  
Author(s):  
S. CHATURVEDI ◽  
V. GUPTA ◽  
G. SÁNCHEZ-COLÓN

It is shown how the two experimentally measurable properties of the mixing matrix V, the asymmetry Δ(V) = |V12|2 - |V21|2 of V with respect to the main diagonal and the Jarlskog invariant [Formula: see text], can be exploited to obtain constraints on possible structures of mass matrices in the quark sector. Specific mass matrices are examined in detail as an illustration.


2007 ◽  
Vol 16 (05) ◽  
pp. 1383-1393 ◽  
Author(s):  
HIDEYUKI SAWANAKA

Realistic quark masses and mixing angles are obtained applying the successful A4 family symmetry for leptons, motivated by the quark-lepton assignments of SU (5). The A4 symmetry is suitable to give tri-bimaximal neutrino mixing matrix which is consistent with current experimental data. We study new scenario for the quark sector with the A4 symmetry.


2012 ◽  
Vol 27 (06) ◽  
pp. 1250026
Author(s):  
S. CHATURVEDI ◽  
V. GUPTA ◽  
G. SÁNCHEZ-COLÓN ◽  
S. RAJPOOT

Using the four best measured moduli of the flavor mixing matrix (|V ud |, |V us |, |V cd |, |V cs |), the Jarlskog invariant J(V), and the quark masses at MZ energy scale as experimental constraints, a statistical comparison of three different types of quark mass matrices in the physical basis is performed. The mass matrices in question are the Chaturvedi–Gupta–Sánchez-Colón (CGS), the Fritzsch and the Gupta–Rajpoot types. With nine parameters the best fits are obtained using a Gupta–Rajpoot-type matrix while with seven parameters the best fits are obtained using the CGS-type matrix. The stability of our analysis with respect to evolution of the quark masses is also presented.


1992 ◽  
Vol 07 (25) ◽  
pp. 6357-6370 ◽  
Author(s):  
ROBERT E. SHROCK

We study an ansatz for the quark mass matrix in which all of the nondiagonal entries are nonzero, but which still allows the quark mixing angles to be calculated in terms of ratios of quark masses and certain phases. Analytic calculations of the orthogonal rotation matrices in the up and down quark sectors and the resultant observed quark mixing matrix are presented. Comparison with experimental data is given.


2013 ◽  
Vol 28 (31) ◽  
pp. 1350131 ◽  
Author(s):  
SRINU GOLLU ◽  
K. N. DEEPTHI ◽  
R. MOHANTA

The recent results from Daya Bay and RENO reactor neutrino experiments have firmly established that the smallest reactor mixing angle θ13 is nonvanishing at the 5 σ level, with a relatively large value, i.e. θ13 ≈ 9°. Using the fact that the neutrino mixing matrix can be represented as [Formula: see text], where Ul and Uν result from the diagonalization of the charged lepton and neutrino mass matrices and Pν is a diagonal matrix containing the Majorana phases and assuming the tri-bimaximal (TBM) form for Uν, we investigate the possibility of accounting for the large reactor mixing angle due to the corrections of the charged lepton mixing matrix. The form of Ul is assumed to be that of CKM mixing matrix of the quark sector. We find that with this modification it is possible to accommodate the large observed reactor mixing angle θ13. We also study the implications of such corrections on the other phenomenological observables.


1993 ◽  
Vol 71 (3-4) ◽  
pp. 172-174
Author(s):  
B. Margolis ◽  
S. Punch

We present mass matrices identical in form for both the up and down quark families, with the following remarkable properties. Both up and down quark masses, at a scale of 1 GeV, are well-approximated by geometric progressions. The five known quark masses and the Kobayashi–Maskawa (KM) mixing matrix agree with experiment. The KM matrix is expressed in terms of only two parameters. We give the KM matrix in the Wolfenstein form.


2006 ◽  
Vol 21 (11) ◽  
pp. 907-910 ◽  
Author(s):  
S. CHATURVEDI ◽  
VIRENDRA GUPTA

It is shown that two specific properties of the unitary matrix V can be expressed directly in terms of the matrix elements and eigenvalues of the hermitian matrix M which is diagonalized by V. These are the asymmetry Δ(V) = |V12|2-|V21|2, of V with respect to the main diagonal and the Jarlskog invariant [Formula: see text]. These expressions for Δ(V) and J(V) provide constraints on possible mass matrices from the available data on V.


2002 ◽  
Vol 17 (10) ◽  
pp. 627-630 ◽  
Author(s):  
ERNEST MA

If the standard model of quark interactions is supplemented by a discrete A4 symmetry (which may be relevant for the lepton sector), the spontaneous breaking of the electroweak gauge symmetry allows arbitrary quark masses, but all mixing angles are predicted to be zero. A pattern of the explicit breaking of A4 is proposed, which results in a realistic charged-current mixing matrix.


2011 ◽  
Vol 26 (09) ◽  
pp. 661-667 ◽  
Author(s):  
HIROYUKI NISHIURA ◽  
TAKESHI FUKUYAMA

We propose a universal mixing hypothesis between quark and lepton sectors at high energy scale (probably GUT scale) where quark–lepton universality holds. Namely in the charged lepton diagonal base, all the other mass matrices for up and down quarks and neutrinos are diagonalized by the same unitary matrix except for the phase elements. Thanks to this hypothesis, the observed values of the Cabibbo–Kobayashi–Maskawa (CKM) quark mixing matrix and the mixing angles θ12 and θ23 in the Maki–Nakagawa–Sakata (MNS) lepton mixing matrix can predict the unknown magnitudes of the mixing angle θ13 and of the CP violating Dirac phase δ in the MNS matrix. Their allowed regions are rather narrow, 0.036 < sin θ13 < 0.048 and 6° < δ < 12°.


2009 ◽  
Vol 24 (18n19) ◽  
pp. 3462-3468 ◽  
Author(s):  
MANMOHAN GUPTA ◽  
GULSHEEN AHUJA ◽  
ROHIT VERMA

Implications of texture specific mass matrices have been investigated for both quarks and neutrinos. Interestingly, for the case of quarks Fritzsch-like texture 4 zero mass matrices have been found to be compatible with the present precisely known sin 2β as well as other precise CKM matrix elements. In the case of leptonic mass matrices, for both Majorana and Dirac neutrinos we find that for texture 4, 5, 6 zero mass matrices the inverted hierarchy and degenerate scenarios of neutrino masses are ruled out by the present data.


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