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1.
Jogesh C. Pati 《Pramana》2004,62(2):513-522
Evidence in favor of supersymmetric grand unification including that based on the observed family multiplet-structure, gauge
coupling unification, neutrino oscillations, baryogenesis, and certain intriguing features of quark-lepton masses and mixings
is noted. It is argued that attempts to understand (a) the tiny neutrino masses (especially Δm
2(v
2 – v3)), (b) the baryon asymmetry of the Universe (which seems to need leptogenesis), and (c) the observed features of fermion
masses such as the ratiom
b/mτ, the smallness ofV
cb and the maximality of
seem to select out the route to higher unification based on an effective string-unifiedG(224) =SU(2)L ×SU(2)R ×SU(2)c orSO(10)-symmetry that should be operative in 4D, as opposed to other alternatives. A predictiveSO(10)/G(224)-framework possessing supersymmetry is presented that successfully describes the masses and mixings of all fermions including
neutrinos. It also accounts for the observed baryon asymmetry of the Universe by utilizing the process of leptogenesis, which
is natural to this framework. It is argued that a conservative upper limit on the proton lifetime within thisSO(10)/G(224)-framework, which is so far most successful, is given by
x 1034 years. This in turn strongly suggests that an improvement in the current sensitivity by a factor of five to ten (compared
to SuperK) ought to reveal proton decay. Implications of this prediction for the next-generation nucleon decay and neutrino-detector
are noted. 相似文献
2.
Starting with the unification hypothesis of mixings of quarks and leptons and small quark-like mixings at the see-saw scale,
we find that two large mixings for νe —νx03BC; andv
μ—v
τ at the weak scale are obtained as a result of renormalization group evolution and radiative magnification if the three neutrinos
are quasi degenerate in masses and possess the same CP parity. We also find thatU
e3
remains small and well within the CHOOZ-Palo Verde bound since the correspondingV
ub
for CKM mixing is very small. Several testable pedictions are pointed out. 相似文献
3.
J. C. Pati 《Physics of Atomic Nuclei》2000,63(6):1058-1077
Following recent joint works with K. Babu and F. Wilczek, I stress here that supersymmetric unification, based on symmetries like SO(10) or a string-derived G(224)=SU(2) L ×SU(2) R ×SU(4) C possesses some crucial features that are intimately linked to each other. They are (a) gauge-coupling unification; (b) the masses and mixings of all fermions, including especially the neutrinos; and last but not least (c) proton decay. In this context, it is noted that the value of $m_{v_L^\tau } \sim 1/20{\text{ }}eV$ , suggested by the Super-Kamiokande result, goes extremely well with the unification-hypothesis, based on the ideas of (i) SU(4)-color, (ii) left-right symmetry, and (iii) supersymmetry. A concrete proposal is presented within an economical SO(10)-framework that makes five successful predictions for the masses and mixings of the quarks and the charged leptons. The same framework explains why the νπ?ντ oscillation angle is so large $(\sin ^2 2\theta _{\nu _\mu \nu _\tau }^{osc} \approx 0.82 - 0.96)$ and yet V bc is so small (≈0.04), both in accord with observation. The influence of the masses of the neutrinos and of the charged fermions on proton decay is discussed concretely, within this framework. The $\bar \nu K^ + $ mode is expected to be dominant for SUSY SO(10) as well as SU(5). A distinctive feature of the SO(10) model, however, is the likely prominence of the μ+ K 0 mode, which, for SU(5), is highly suppressed. Our study shows that while current limits on the rate of proton decaying into $\bar \nu K^ + $ are compatible with theoretical expectations, improvements in these limits by a factor of 5–10 should either turn up events, or else the SO(10)-framework described here, which is otherwise so successful, will be in jeopardy. Prominence of theμ+ K 0 mode, if observed, will be most significant in that it will reveal the intriguing link that exists between neutrino masses and proton decay in the context of supersymmetric unification. 相似文献
4.
In the framework of a left–right model containing mirror fermions with gauge group SU(3)
C
⊗SU(2)
L
⊗SU(2)
R
⊗U(1)
Y′, we estimate the neutrino masses, which are found to be consistent with their experimental bounds and hierarchy. We evaluate
the decay rates of the Lepton Flavor Violation (LFV) processes μ→eγ, τ→μγ and τ→eγ. We obtain upper limits for the flavor-changing branching ratios in agreement with their present experimental bounds. We
also estimate the decay rates of heavy Majorana neutrinos in the channels N→W
±
l
∓, N→Zν
l
and N→Hν
l
, which are roughly equal for large values of the heavy neutrino mass. Starting from the most general Majorana neutrino mass
matrix, the smallness of active neutrino masses turns out from the interplay of the hierarchy of the involved scales and the
double application of seesaw mechanism. An appropriate parameterization on the structure of the neutrino mass matrix imposing
a symmetric mixing of electron neutrino with muon and tau neutrinos leads to tri-bimaximal mixing matrix for light neutrinos. 相似文献
5.
Results from Super-Kamiokande-I’s entire 1496 live days of solar neutrino data are presented, including the absolute flux,
energy spectrum, zenith angle (day/night) and seasonal variation. The possibility of MSW and vacuum oscillations is discussed
in light of these results. Results from the first 1289 days of Super-K-I’s atmospheric neutrino analysis are also presented,
including the evidence for νμ →ν
τ oscillations, against νμ → νsterile oscillations, and the current limits on proton decay. Finally, results based on 56 × 1019 protons on target are given for the K2K long-baseline neutrino oscillation experiment. 相似文献
6.
Ahmed Ali Fernando Barreiro Javier Llorente 《The European Physical Journal C - Particles and Fields》2011,71(9):1737
We present an analysis with improved sensitivity to the light charged Higgs (mH+ < mt-mbm_{H^{+}} < m_{t}-m_{b}) searches in the top quark decays t→bH
+→b(τ
+
ν
τ
)+c.c. in the t[`(t)]t\bar{t} and single t/[`(t)]t/\bar{t} production processes at the LHC. In the Minimal Supersymmetric Standard Model (MSSM), one anticipates the branching ratio
B (H+ ?t+nt) @ 1{\mathcal{B}} (H^{+} \to\tau^{+}\nu_{\tau})\simeq1 over almost the entire allowed tanb\tan\beta range. Noting that the τ
+ arising from the decay H
+→τ
+
ν
τ
are predominantly right-polarized, as opposed to the τ
+ from the dominant background W
+→τ
+
ν
τ
, which are left-polarized, a number of H
+/W
+→τ
+
ν
τ
discriminators have been proposed and studied in the literature. We consider hadronic decays of the τ
±, concentrating on the dominant one-prong decay channel τ
±→ρ
±
ν
τ
. The energy and p
T
of the charged prongs normalised to the corresponding quantities of the ρ
± are convenient variables which serve as τ
± polariser. We use the distributions in these variables and several other kinematic quantities to train a boosted decision
tree (BDT). Using the BDT classifier, and a variant of it called BDTD, which makes use of decorrelated variables, we have
calculated the BDT(D)-response functions to estimate the signal efficiency vs. the rejection of the background. We argue that
this chain of analysis has a high sensitivity to light charged Higgs searches up to a mass of 150 GeV in the decays t→bH
+ (and charge conjugate) at the LHC. For the case of single top production, we also study the transverse mass of the system
determined using Lagrange multipliers. 相似文献
7.
We present a detailed calculation of the contributions of charginos, scalar quarks, and charged Higgs boson to theK
+→π
+
vv andK
L
0
→μ
+
μ
− decays. We include mixings: that of charginos and that of the scalar partners of the left and right handed top quark. We
find that the box contribution to the amplitudes is much smaller than the penguin contribution, which can be ∼10% of the Standard
Model contribution, even for relatively large SUSY masses. The charged Higgs contribution can be as large as 25% of the SM
contribution in the first decay and as much as 40% of the SM contribution in the second decay. 相似文献
8.
Edward A. Desloge 《International Journal of Theoretical Physics》1976,15(5):357-363
On the basis of elementary symmetry arguments it is shown that (1) if in classical mechanics there exists a quantity λ+Σiμiυi+1/2νυ
2 that is conserved, where λ,μ
i, andν are particle parameters, then theμ
i andν are all proportional to a single parameterμ and the quantityAμ+ΣiBiμυi+C(λ+ 1/2Dμυ
2), whereD ≡ν/μ, is conserved for all values ofA, B
i, andC; (2) if in relativistic mechanics there exists a quantity λ+Σiμiυi[1−(υ
2/c
2)]−1/2+νc[1−(υ
2/c
2)]−1/2 that is conserved, then theμ
i andν are all proportional to a single parameterμ and the quantityAλ+ΣiBiμνi[1−(υ
2/c
2)]−1/2+Cμc [1−(υ
2/c
2)]−1/2 is conserved for all values ofA, B
i, andC. 相似文献
9.
The Geant4 CHIPS model simulates both decay and nuclear capture of negative muons. In hadron level models the muon is captured
by a proton, p(μ,νμ)n , and the neutron transfers to the nucleus only 5MeV, which is not enough to split a nucleon from the nucleus, while the
measured spectra of emitted nucleons reach 80MeV. In CHIPS, which considers asymptotically free quark-partons, the muon can
be captured by a quark, u(μ,νμ)d , and transfers 52MeV to the nucleus. This capture mechanism fits the main part of the nucleon spectra, while the high-energy
part of the spectra is not fitted. A precise fit of the high-energy part of the nucleon spectra can be made if the muon decay
μ → dˉνμ is taken into account. 相似文献
10.
Stuart Raby 《Pramana》2004,62(2):523-536
In this talk I define what I call the minimalSO(10) SUSY model. I then discuss the phenomenological consequences of this theory, vis-a-vis gauge and Yukawa coupling unification,
Higgs and super-particle masses, the anomalous magnetic moment of the muon, the decayB
s → μ+ itμ− and dark matter.
On leave of absence at the Institute for Advanced Study, Princeton, NJ, USA 相似文献
11.
For aL
∞
(ℝ+)∩L
1
(ℝ+) the truncated Bessel operator B
τ
(a) is the integral operator acting on L
2
[0,τ] with the kernel
where J
ν
stands for the Bessel function with ν>−1. In this paper we determine the asymptotics of the determinant det(I+B
τ
(a)) as τ→∞ for sufficiently smooth functions a for which a(x)≠1 for all x[0,∞). The asymptotic formula is of the form det(I+B
τ
(a))∼G
τ
E with certain constants G and E, and thus similar to the well-known Szeg?-Akhiezer-Kac formula for truncated Wiener-Hopf determinants.
Received: 23 April 2002 / Accepted: 25 September 2002 Published online: 24 January 2003
RID="*"
ID="*" Supported in part by NSF Grant DMS-9970879.
Communicated by J.L. Lebowitz 相似文献
12.
R. Gheisari 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(2):193-196
We calculate decay widths of the metastable ppμ*
ν,J molecular ion in non-adiabatic approach. The muonic molecular ion can be formed in collision of the excited pμ(2s) atoms
with H2. Then, decay of the ppμ*
ν,J system opens a path for the muon from pμ(2s) to pμ(1s). We employ trial wave function which includes non-adiabatic terms
to calculate some radiationless decay widths. The present results of the widths do not good agree with those given in our
previous work, while are more close to recent data of other researchers. 相似文献
13.
Yoshio Koide 《The European Physical Journal C - Particles and Fields》2007,50(4):809-816
Based on the universal seesaw mass matrix model with the three scalars φi, and by assuming S3 flavor symmetry for the Yukawa interactions, the lepton masses and mixings are investigated systematically. In order to understand
the observed neutrino mixing, the charged leptons (e,μ,τ) are regarded as the three objects (e1,e2,e3) of S3, while the neutrino mass eigenstates are regarded as the irreducible representation (νη,νσ,νπ) of S3, where (νπ,νη) and νσ are a doublet and a singlet, respectively, which are composed of the three objects (ν1,ν2,ν3) of S3. 相似文献
14.
Edward A. Desloge 《International Journal of Theoretical Physics》1976,15(5):349-356
On the basis of simple kinematic arguments it is shown that any quantity, depending only on the nature and velocity of a particle,
that is conserved in a collision must, in classical mechanics, be of the form λ+Σiμiυi+1/2vυ
2 or in relativistic mechanics of the form λ+Σiμiυi[1−(υ
2/c
2)]−1/2+νc [1−(υ
2/c
2)]−1/2 where λ,μ
i, andν are particle parameters. 相似文献
15.
We look at the confinement of tensor gluons (f
μν
(c)
field) in a strong gravity background and find that the strong gravity provides a trap for the confinement of colour waves
of selected frequencies. We assume that the tensorf
μν
(c)
field (mediating quanta: tensor 2+
f-meson) satisfies Einstein-like equations with a cosmological constant. The colour field satisfy equations resembling Maxwell
form of the linear theory of gravitation and see the effect off
μν
(c)
field as playing the role of a medium having space dependent dielectric permeabilities. The solution of colour field equations
resemble harmonic oscillator type wave functions with equispaced energy levels (no continuum) leading to confinement. 相似文献
16.
V. Bashiry 《The European Physical Journal C - Particles and Fields》2006,47(2):423-428
In this paper we study the lepton polarization asymmetry for the semileptonic OZI-forbidden annihilation decay B-
c→η’ℓ-ν̄, where ℓ=μ,τ. Our results show that the branching ratios turn out to be of order 10-4. Besides, we find that longitudinal, transversal and normal components of lepton polarizations can be measured for both μ
and τ decay modes in the future experiments at the LHC.
PACS 14.40.Nd; 13.20.He; 13.60.-r; 11.30.Er 相似文献
17.
F. Šimkovic 《Physics of Particles and Nuclei》2011,42(4):598-612
The fundamental importance of searching for neutrinoless double-beta decay (0νββ-decay) is widely recognized. Observation
of the decay would tell us that the total lepton number is not conserved and that, consequently, neutrinos are massive Majorana
fermions. A brief history of the double-beta decay is presented. The 0νββ-decay is discussed in context of neutrino oscillation
data. The perspectives of the experimental 0νββ-decay searches are analyzed. The importance of reliable determination of the
0νββ-decay nuclear matrix elements is pointed out. The problem of distinguishing of the light-neutrino exchange, heavy-neutrino
exchange and the trilinear R-parity breaking supersymmetric (
\not Rp \not R_p SUSY) mechanisms of the 0νββ-decay is addressed. Further, the process of resonant neutrinoless double-electron capture (0νɛɛ)
is revisited. Arguments are presented that an experimental search for the 0νɛɛ might be feasible. 相似文献
18.
S. N. Nakamura D. Tomono Y. Matsuda G. Mason M. Iwasaki K. Ishida T. Matsuzaki I. Watanabe S. Sakamoto K. Nagamine 《Hyperfine Interactions》2001,138(1-4):445-450
The lifetime of the positive muon (τμ
+) can be directly associated with the Fermi Coupling Constant (G
F
), which is one of the most basic parameters of the Standard Model. However, the current experimental accuracy of the τμ
+ is ∼30 ppm and it has not been improved for more than 15 years. We propose a new experiment for a pulsed muon facility such
as RIKEN-RAL to measure the muon lifetime with multi-decay per one time window method. The advantage of our setup, no time
window limitation, enables us to test the exponential decay law (EDL) in the long decay time region at the same time. The
preliminary analysis set a new upperlimit for the EDL deviation in the muon decay. We accumulated ∼1010 muon decays and analysis is in progress.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
C. Jollet 《Physics of Atomic Nuclei》2006,69(11):1872-1875
The aim of the OPERA experiment is to provide unambiguous evidence for the ν
μ ↔ ν
τ oscillation by looking at the appearance of ν
τ in a pure ν
μ beam. This oscillation will be sought in the region of the oscillation parameters indicated by the atmospheric neutrino results.
The experiment is part of the CNGS (CERN Neutrino beam to Gran Sasso) project. The ν
μ beam produced at CERN will be sent towards the Gran Sasso underground laboratory, where the OPERA detector is under construction.
The detector, the physics potential, and performance for neutrino oscillation studies including the subleading ν
μ ↔ ν
ε search are presented.
The text was submitted by the author in English. 相似文献
20.
S. G. Karshenboim V. G. Ivanov U. D. Jentschura G. Soff 《Journal of Experimental and Theoretical Physics》1998,86(2):226-236
We examine the properties of an atomic system consisting of a muon and antimuon. Expressions are derived for the probability
of decay and the hyperfine splitting of the lower levels with allowance for the leading radiative corrections, which are of
relative order α. The results for the lifetimes and the ground-state energy are τ(13
S
1)=1.7907(8)×10−12 s, τ(11
S
0)=0.59547(33)×10−12 s, and E
hfs (1s)=4.23284(35)×107 MHz. The relative probabilities for the various decay channels are calculated; in particular, for the 1 3
S
1 level it is found that Γ (μμ→eeγ)/Γ(μμ→ee)≈15%. Finally, possible applications are discussed.
Zh. éksp. Teor. Fiz. 113, 409–431 (February 1998) 相似文献