119989444
Future constraints on and from lepton universality
In the near future, experimental constraints on charged current (CC) lepton universality can be expected to improve dramatically. First, the PIENU experiment at TPIUMF and the PEN experiment at PSI aim to improve the bound on the ratio by almost an order of magnitude. Second, by analyzing existing data, the Belle experiment aims to improve the bound on the ratio by a factor of three. Further improvements can be expected by analyzing the τ decays in existing Belle data. There also exist a large amount of unanalyzed W decay data from the Tevatron. These new bounds will place very tight constraints on possible new physics beyond the Standard Model. For example, the 95% bounds on R-parity violating couplings will be improved as follows: These limits will be very difficult to improve further, even with future high statistics neutrino experiments such as NuSOnG [1]. However, for certain types of new physics, the combination of CC lepton universality data and NuSOnG will have a dramatic effect. I demonstrate this using a model in which neutrino mixing with heavy gauge singlet states suppress both the CC and NC neutrino couplings.
64343483
Position and momentum uncertainties of a particle in a V-shaped potential under the minimal length uncertainty relation
We calculate the uncertainties in the position and momentum of a particle in the 1D potential V (x) = F|x|, F > 0, when the position and momentum operators obey the deformed commutation relation [x,p] = iℏ(1 + βp2), β > 0. As in the harmonic oscillator case, which was investigated in a previous publication, the Hamiltonian Ĥ1 = p2/2m + F|x| admits discrete positive energy eigenstates for both positive and negative mass. The uncertainties for the positive mass states behave as Δx ∼ 1/Δp as in the β = 0 limit. For the negative mass states, however, in contrast to the harmonic oscillator case where we had Δx ∼ Δp, both Δx and Δp diverge. We argue that the existence of the negative mass states and the divergence of their uncertainties can be understood by taking the classical limit of the theory. Comparison of our results is made with previous work by Benczik.
54186542
Position and Momentum Uncertainties of the Normal and Inverted Harmonic Oscillators under the Minimal Length Uncertainty Relation
p 2 ). This deformed commutation relation leads to the minimal length uncertainty relationx � (~/2)(1/�p + ��p), which implies thatx � 1/�p at smallp whilex � �p at largep. We find that the uncertainties of the energy eigenstates of the normal harmonic oscillator (m > 0), derived in Ref. (1), only populate thex � 1/�p branch. The other branch, �x � �p, is found to be populated by the energy eigenstates of the 'inverted' harmonic oscillator (m p 2(~ 2 /k|m|) 1/4 . Correspondence with the classical limit is also discussed.
16530141
Constraints placed on the Higgs sector from precision electroweak measurements
In this lecture, I would like to investigate what precision electroweak measurements have to tell us about the Higgs sector. I will show that the radiative corrections to electroweak interaction observables coming from the Higgs sector can be summarized into three parameters S, T, and U. The precision measurements of the observables will constrain S and T. By comparing these constraints with the theoretically predicted values of S and T, we will be able to tell which Higgs sector theories are more viable than others. 24 refs., 3 figs.
119450303
Indirect probes of new physics
We summarize the indirect effects of new physics in a variety of processes. We consider precision electroweak measurements, the $g-2$ of the muon, rare decays, meson mixing, CP violation, lepton number violating interactions, double beta decay, and the electric dipole moments of atoms, molecules, and the neutron. We include discussions of both model independent and dependent analyses where applicable.
444650
Oblique corrections to the W width.
The lowest-order expression for the partial $W$ width to $e \nu ,~\Gamma (W \to e \nu) = G_\mu M_W^3 /(6 \pi \sqrt{2})$, has no oblique radiative corrections from new physics if the measured $W$ mass is used. Here $G_\mu = (1.16639 \pm 0.00002) \times 10^{-5}$ GeV/$c^2$ is the muon decay constant. For the present value of $M_W = (80.14 \pm 0.27)$ GeV/$c^2$, and with $m_t = 140$ GeV$/c^2$, one expects $\Gamma (W \to e \nu) = (224.4 \pm 2.3)$ MeV. The total width $\Gamma_{\rm tot}(W)$ is also expected to lack oblique corrections from new physics, so that $\Gamma_{\rm tot} (W)/ \Gamma (W \to e \nu) = 3 + 6 [1 + \{\alpha_s (M_W)/\pi \}]$. Present data are consistent with this prediction.
215736286
STATUS AND PERSPECTIVE OF THE NB3AL DEVELOPMENT IN JAPAN
The RHQT process enables to form a stoichiometric Nb3Al with fine-grain structures via a bcc supersaturated solid solution and so that a large Jc is achieved over the whole range of magnetic fields without trading off the excellent strain tolerance. A long-length of RHQ processing has been established, and a rectangular but Cu stabilized Nb3Al strand is about to be commercially available for NMR uses. Another stabilization technique has been developed and likely applicable to accelerator uses. Research activities at the KEK with respect to the low field Jc characterization are also described.
140060327
Nb-3_Al high field accelerator magnet \&