A
bstract
In this paper we discuss the possibility of measuring the anomalous magnetic and electric dipole moments of the
τ
lepton. The method consists in studying the spin precession induced by the ...strong effective magnetic field inside channels of a bent crystal with a dedicated setup at the CERN Large Hadron Collider.
A
bstract
In this paper we revisit the idea of measuring the magnetic dipole moments of the charm baryons and, in particular, of
Λ
c
+
by studying the spin precession induced by the strong effective ...magnetic field inside the channels of a bent crystal. We present a detailed sensitivity study showing the feasibility of such an experiment at the LHC in the coming years.
In this paper, we discuss the theoretical framework and the experimental measurements of the magnetic moment of the charmed baryons. We first review the theoretical predictions of the
Λ
c
+
magnetic ...moment and show that the measurements of the magnetic moments of other charmed baryons, such as
Ξ
c
, allow to perform detailed spectroscopy studies. The magnetic moment of the charm quark can be determined using radiative charmonium decay, which can be compared to the
Λ
c
+
magnetic moment within theoretical models. The present results show a tension with majority of theoretical predictions. The magnetic moment of the charmed baryons could potentially be measured directly, using bent-crystal experiments at LHC. The possibility to measure precisely the magnetic moments of charmed baryons needs precise measurement of their polarisation and weak decay parameters. In this paper, we revisit the formalism of the angular analysis needed for these measurements and make a detailed evaluation of initial polarisation of deflected
Λ
c
baryons as a function of crystal orientation. We found a special orientation of the crystal that gives the opportunity to measure the
Λ
c
dimensionless electric dipole moment almost with the same precision as its
g
-factor, which is more than an order of magnitude more efficient than suggested before.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We update the constraints on new-physics contributions to ΔF = 2 processes from the generalized unitarity triangle analysis, including the most recent experimental developments. Based on these ...constraints, we derive upper bounds on the coefficients of the most general ΔF = 2 effective Hamiltonian. These upper bounds can be translated into lower bounds on the scale of new physics that contributes to these low-energy effective interactions. We point out that, due to the enhancement in the renormalization group evolution and in the matrix elements, the coefficients of non-standard operators are much more constrained than the coefficient of the operator present in the Standard Model. Therefore, the scale of new physics in models that generate new ΔF = 2 operators, such as next-to-minimal flavour violation, has to be much higher than the scale of minimal flavour violation, and it most probably lies beyond the reach of direct searches at the LHC.
•The new PARC_CL 2.0 reinforced concrete model is proposed.•PARC_CL 2.0 is applied to the analysis of a wall structure shaking table test.•Local and global engineering demand parameters are ...evaluated.•The proposed modelling provides results in agreement with the experimental data.
Presented in the paper is the new PARC_CL 2.0 crack model, a physical approach for RC modelling especially tailored to shear sensitive structures. The model is then applied for the seismic response assessment of the SMART 2013 specimen, a scaled RC nuclear power plants facility wall structure tested on a shaking table under strong seismic input. The aim of the research is to evaluate the predictive capacity of the modelling in terms of global and local response, in order to try to partially fill the gap for the need of non linear calculation for large structures and applicability of the modelling technique to the practice. The presented approach demonstrated to be able to provide satisfying results in terms of top displacement, floor acceleration spectra, interstorey drift and eigen frequency drop off. Moreover, the modelling using shell elements demonstrated to keep the amount of computational cost acceptable.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
PERLE (Powerful Energy Recovery LINAC for Experiment) is a three turns high-power Energy Recovery LINAC (ERL) facility with 20 mA beam current and beam energy from 250 MeV to 500 MeV. It is ...a testbed to validate multi-turn high current ERL operation for the future LHeC and will be the first ERL for nuclear applications. In this work, the design and optimization of the commutational magnet (B-com) used to spread/combine the three beams and one series of quadrupole magnets is discussed. The B-com magnet is optimized for a 30° bending angle with harmonic content of 0.036%. The quadrupole magnets generate a field gradient of 34.15 T/m. Further studies to suppress saturation at a maximum gradient of 44.1 T/m are undergoing.
The status of the unitary triangle beyond the standard model including the most recent results on Deltams on dilepton asymmetries and on width differences is presented. Even allowing for general new ...physics loop contributions the unitarity triangle must be very close to the standard model result. With the new measurements from the Fermilab Tevatron, we obtain for the first time a significant constraint on new physics in the Bs sector. We present the allowed ranges of new physics contributions to DeltaF=2 processes and of the time-dependent CP asymmetry in Bs-->J/psivarphi decays.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
A new kind of nonresonant optical recirculator, dedicated to the production of γ rays by means of Compton backscattering, is described. This novel instrument, inspired by optical multipass systems, ...has its design focused on high flux and very small spectral bandwidth of the γ -ray beam. It has been developed to fulfill the project specifications of the European Extreme Light Infrastructure “Nuclear Pillar,” i.e., the Gamma Beam System. Our system allows a single high power laser pulse to recirculate 32 times synchronized on the radio frequency driving accelerating cavities for the electron beam. Namely, the polarization of the laser beam and crossing angle between laser and electrons are preserved all along the 32 passes. Moreover, optical aberrations are kept at a negligible level. The general tools developed for designing, optimizing, and aligning the system are described. A detailed simulation demonstrates the high efficiency of the device.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM, UPUK
The recently measured B→τν branching ratio allows to test the Standard Model by probing virtual effects of new heavy particles, such as a charged Higgs boson. The accuracy of the test is currently ...limited by the experimental error on BR(B→τν) and by the uncertainty on the parameters fB and |Vub|. The redundancy of the Unitarity Triangle fit allows to reduce the error on these parameters and thus to perform a more precise test of the Standard Model. Using the current experimental inputs, we obtain BR(B→τν)SM=(0.84±0.11)×10−4, to be compared with BR(B→τν)exp=(1.73±0.34)×10−4. The Standard Model prediction can be modified by New Physics effects in the decay amplitude as well as in the Unitarity Triangle fit. We discuss how to disentangle the two possible contributions in the case of minimal flavour violation at large tanβ and generic loop-mediated New Physics. We also consider two specific models with minimal flavour violation: the Type-II Two Higgs Doublet Model and the Minimal Supersymmetric Standard Model.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Using the latest determinations of several theoretical and experimental parameters, we update the Unitarity Triangle analysis in the Standard Model. The basic experimental constraints come from the ...measurements of |V_ub/V_cb|, Delta M_d, the lower limit on Delta M_s, epsilon_k, and the measurement of the phase of the B_d - anti B_d mixing amplitude through the time-dependent CP asymmetry in B^0 to J/psi K^0 decays. In addition, we consider the direct determination of alpha, gamma, 2 beta + gamma and cos(2 beta) from the measurements of new CP-violating quantities, recently performed at the B factories. We also discuss the opportunities offered by improving the precision of the various physical quantities entering in the determination of the Unitarity Triangle parameters. The results and the plots presented in this paper can also be found at www.utfit.org, where they are continuously updated with the newest experimental and theoretical results.
PDF
