29,125 research outputs found
Discrete Symmetry and CP Phase of the Quark Mixing Matrix
A simple specific pattern of the two 3 X 3 quark mass matrices is proposed,
resulting in a prediction of the CP phase of the charged-current mixing matrix
V_CKM, i.e. sin 2 phi_1 (beta) = 0.733, which is in remarkable agreement with
data, i.e. sin 2 phi_1 = 0.728 +/- 0.056 +/- 0.023 from Belle and sin 2 beta =
0.722 +/- 0.040 +/- 0.023 from Babar. This pattern can be maintained by a
discrete family symmetry, an example of which is D_7, the symmetry group of the
heptagon.Comment: 9 pages, no figur
Exotic Fermions and Bosons in the Quartification Model
Exotic fermions of half-integral charges at the TeV energy scale are
predicted by the quartification model of Babu, Ma, and Willenbrock. We add to
these one copy of their scalar analogs and discuss the ensuing phenomenological
implications, i.e. radiative contributions to lepton masses and flavor-changing
leptonic decays.Comment: 7 pages, including 3 figure
Quantum Game with Restricted Matrix Strategies
We study a quantum game played by two players with restricted multiple
strategies. It is found that in this restricted quantum game Nash equilibrium
does not always exist when the initial state is entangled. At the same time, we
find that when Nash equilibrium exists the pay off function is usually
different from that in the classical counterpart except in some special cases.
This presents an explicit example where quantum game and classical game may
differ. When designing a quantum game with limited strategies, the allowed
strategy should be carefully chosen according to the type of initial state.Comment: 5 pages and 3 figure
Ultrasensitive detections in atomic and molecular physics: demonstration in molecular overtone spectroscopy
We consider several highly sensitive techniques commonly used in detection of atomic and molecular absorptions. Their basic operating principles and corresponding performances are summarized and compared. We then present our latest results on the ultrasensitive detection of molecular overtone transitions to illustrate the principle and application of the cavity-enhanced frequency-modulation (FM) spectroscopy. An external cavity is used to enhance the molecular response to the light field, and an FM technique is applied for shot-noise-limited signal recovery. A perfect match between the FM sideband frequency and the cavity free spectral range makes the detection process insensitive to the laser-frequency noise relative to the cavity, and, at the same time, overcomes the cavity bandwidth limit. Working with a 1.064-µm Nd:YAG laser, we obtained sub-Doppler overtone resonances of C2HD, C2H2, and CO2 molecules. A detection sensitivity of 5 x 10^-13 of integrated absorption (1 x 10^-14/cm) over 1-s averaging time has been achieved
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