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1.
A systematic semiquantitative account of all aspects of the strong and electromagnetic interactions of all the newly discovered hadronic states (theψ’s, theχ’s, etc.) is presented within the framework of the paracharge scheme. Extensions of ideas familiar from the SU3 classification scheme to SU4 are shown to provide an understanding of the new states seen in the decays ofψ (3.1) andψ′ (3.7), including their masses and gross decay characteristics. The decays ofψ (3.1) andψ′ (3.7) themselves are studied in some detail. Since these are of electromagnetic origin in the scheme, their electromagnetic mixing with the resonance at 4.15 GeV (theP-state of the scheme) is important. Once this is taken into account, the resulting picture is in excellent agreement with available data.  相似文献   

2.
I present a brief overview of measurements and calculations that establish the unitarity of the Cabibbo–Kobayashi–Maskawa matrix. I also discuss two experimental programs related to checking the unitarity of the CKM matrix: one tests isospin-breaking corrections using T=2 decays; and the other is an experiment to measure the beta asymmetry from polarized Ultra-cold Neutrons (UCNs), which could yield an accurate determination of V ud with different systematic uncertainties than existing data. Supported by the U.S. Department of Energy.  相似文献   

3.
The recently discovered narrow peaks (theψ-particles) in e+e system at 3.105 and 3.695 GeV are interpreted as hadrons in a broken SU4 symmetry scheme. A new additional additive quantum number, parachargeZ, is combined with the usual SU3 quantum numbers in the group SU4. Theψ (3.1) is assigned to a near ideally mixed151 multiplet of vector mesons (containing theρ) as theI=Y=0, charge conjugationC=−combination ofZ=±1.members. Theψ (3.7) is assigned correspondingly to another mixed151 multiplet containing theρ′ (1600). The hadronic electromagnetic interactions are modified by the addition of (non-minimal) anomalous pieces that can changeZ. The decays of theψ-particles are discussed. New enlarged SU4 multiplets of other hadrons are proposed. Tests of our scheme are put forward. The most crucial test will be the observation of two rather broad resonances in e+ e collisions with masses around 4.2 GeV and 5.1 GeV. Another prediction is the presence of energetic photons in the decays of theψ-particles. Important results concerning the recently observed phenomena in the process e+e→hadrons follow in this scheme.  相似文献   

4.
Harpreet Kaur 《Pramana》1999,52(4):389-393
The beauty-conserving strangeness-changing decays ofB s meson are examined. In the charm sector, charm-conserving strangeness changing (Δc = 0, Δs ≠ 0) decays are Cabibbo suppressed and are governed by the CKM elementV us which is much smaller than the CKM diagonal elementV cs, so may be of little interest. On the other hand, in theb-sector, beauty-conserving strangeness changing (Δb = 0, Δs ≠ 0) decays are CKM allowed as the CKM matrix elementV us governing such decays is much larger thanV bc orV bu which govern respectively thebc orbu transitions. The phase space available, however, is too small for the decays considered here. The numerical estimates for the decay widths of two such modes ofB s meson are presented.  相似文献   

5.
We briefly discuss the large-Nc picture for excited baryons, present a new method for the calculation of matrix elements and illustrate it by computing the strong decays of heavy exotic states.  相似文献   

6.
Chao-Hsi Chang 《Pramana》2000,55(1-2):283-288
The properties of the meson B c are outlined. The leptonic radiative decays for B c meson are presented. An outlook on the studies of the meson is given.  相似文献   

7.
We discuss a possible interpretation of the f 0(980)-meson as a hadronic molecule —a bound state of K and mesons. Using a phenomenological Lagrangian approach we calculate the strong f 0(980) → ππ and electromagnetic f 0(980) → γγ decays. The compositeness condition provides a self-consistent method to determine the coupling constant between f 0 and its constituents, K and . Form factors governing the decays of the f 0(980) are calculated by evaluating the kaon loop integrals. The predicted f 0(980) → ππ and f 0(980) → γγ decay widths are in good agreement with available data and results of other theoretical approaches.  相似文献   

8.
The single-sided NMR-MOUSE sensor that operates in highly inhomogeneous magnetic fields is used to record a CPMG 1H transverse relaxation decay by CPMG echo trains for a series of cross-linked natural rubber samples. Effective transverse relaxation rates 1/T2,short and 1/T2,long were determined by a bi-exponential fit. A linear dependence of transverse relaxation rates on cross-link density is observed for medium to large values of cross-link density. As an alternative to multi-exponential fits the possibility to analyze the dynamics of soft polymer network in terms of multi-exponential decays via the inverse Laplace transformation was studied. The transient regime and the effect of the T1/T2 ratio in inhomogeneous static and radiofrequency magnetic fields on the CPMG decays were studied numerically using a dedicated C++ program to simulate the temporal and spatial dependence of the CPMG response. A correction factor T2/T2,eff is derived as a function of the T1/T2 ratio from numerical simulations and compared with earlier results from two different well logging devices. High-resolution T1T2 correlations maps are obtained by two-dimensional Laplace inversion of CPMG detected saturation recovery curves. The T1T2 experimental correlations maps were corrected for the T1/T2 effect using the derived T2/T2,eff correction factor.  相似文献   

9.
Ramesh C Verma  M P Khanna 《Pramana》1978,11(3):333-351
Weak decay modes (1/2+ → 3/2+ + 0/γ) of charmed baryons are studied. Relations among the various decay amplitudes are derived in isospin, SU(3), SU(4) and SU(8) w symmetries. Sextet dominance in SU(3) forbidsB(3) →D(10) +P(3*) decays. 20″ dominance in SU(4) specifies all the decays in terms of Θ decays. Weak decays of Θ* 3 ++ and Θ are also discussed. SU(8) w symmetry predictsα , which is consistent with the experimental value.  相似文献   

10.
Gobinda Majumder 《Pramana》2004,62(3):587-590
Semileptonic decays ofBX u lv have great importance both from theoretical and experimental point of view, as they are useful for extracting the magnitude ofV ub, one of the tiniest elements of CKM matrix. Similarly measurement ofB √ Ds×u can be used to calculateV ub The Belle Collaboration has measured these branching ratios and extractedV ub for various theoretical models.  相似文献   

11.
The production of σ and κ in J/ψ decays is presented using 58 million J/ψ events collected at BES II detector. We also report the study of the light scalar mesons f 0(980), f 0(1370), f 0(1500) and f 0(1710) etc. in J/ψ decays.  相似文献   

12.
The importance of a super-B factory in the search for new physics, in particular, due to CP-odd phase(s) from physics beyond the standard model is surveyed. The first point to emphasize is that we now know how to directly measure all three angles of the unitarity triangle very cleanly, i.e. without theoretical assumptions with irreducible theory error ≲1%. However, this requires much more luminosity than is currently available atB-factories. Direct searches via penguin-dominated hadronic modes as well as radiative, pair-leptonic and semi-leptonic decays are also discussed. Null tests of the SM are stressed as these will play a crucial role especially if the effects of BSM phase(s) onB-physics are small.  相似文献   

13.
Rahul Sinha 《Pramana》2000,55(1-2):219-228
We review the effects of new physics on CP asymmetries and decays of B mesons. Possible sources and corresponding signals for new physics are studied briefly. We discuss how the decay mode bs ℓℓ (and BK*ℓℓ) will enable us to understand the nature of new physics. We also examine the possibility of truly clean signature of new physics — a signature based on observables alone and without hadronic uncertainties.  相似文献   

14.
The growth, XRD patterns, spectral properties, and fluorescence decays of Yb:Ca0.28Ba0.72Nb2O6 (Yb:CBN) with doping concentration of 1 at.% and 5 at.% were studied. The peak absorption cross-section and the emission cross-section were calculated. Larger Stark splitting of Yb:CBN offers the prospect of the quasi-four level laser operation.  相似文献   

15.
I discuss the prospects for future studies of parity-violating (PV) interactions at low energies and the insights they might provide about open questions in the standard model as well as physics that lies beyond it. I cover four types of parity-violating observables: PV electron scattering; PV hadronic interactions; PV correlations in weak decays and searches for the permanent electric dipole moments of quantum systems.  相似文献   

16.
We investigate the radiative decays of the φ-meson to the scalar mesons a0(980) and f0(980). We demonstrate that, contrary to earlier claims, these decays should be of the same order of magnitude for a molecular state and for a compact state and, therefore, the available experimental information is consistent with both a molecular as well as a compact structure of the scalars. Thus, the radiative decays of the φ-meson into scalars establish a sizable K¯ component of the scalar mesons, but do not allow to discriminate between molecules and compact states.  相似文献   

17.
We report the results of Monte Carlo simulation of the phase diagram and oxygen ordering in YBa2Cu3O6+x for low intra-sublattice repulsion. At low temperatures, apart from tetragonal (T), orthorhombic (OI) and ‘double cell’ ortho II phases, there is evidence for two additional orthorhombic phases labelled here asOI andOIII. At high temperatures, there was no evidence for the decomposition of theOI phase into theT andOI phases. We find qualitative agreement with experimental observations and cluster-variation method results.  相似文献   

18.
Taking into account effects of late energy injection, we examine big bang nucleosynthesis (BBN) constraints on axino dark matter scenarios with long-lived charged sleptons. We calculate 4-body slepton decays into the axino, a lepton, and a quark–antiquark pair since they govern late hadronic energy injection and associated BBN constraints. For supersymmetric hadronic axion models, we present the obtained hadronic BBN constraints and show that they can be more restrictive than the ones associated with catalyzed BBN via slepton-bound-state formation. From the BBN constraints on hadronic and electromagnetic energy release, we find new upper limits on the Peccei–Quinn scale.  相似文献   

19.
The inclusive production rate of the ρ±(770) vector meson in hadronic Z decays is measured with the ALEPH detector at the LEP collider. A total of 3.2 million hadronic events are selected from data recorded between 1991 and 1995. Decays of ρ±π0+π± are reconstructed for xE>0.05 and xp>0.05 where xp=pρ/pbeam and xE=Eρ/Ebeam. The average ρ± multiplicity per hadronic event is evaluated to be N(ρ±)=2.59±0.03±0.15±0.04 where the first error is statistical and the second systematic. The third error is from the uncertainty in the extrapolation to xp=xE=0. The rates and differential cross-section are compared with Monte Carlo model predictions and OPAL measurements. Residual Bose–Einstein correlations are found to be an important component in the analysis.  相似文献   

20.
Yong-Yeon Keum 《Pramana》2004,63(6):1151-1170
We discuss applications of the perturbative QCD approach in the exclusive non-leptonic two-bodyB-meson decays. We briefly review its ingredients and some important theoretical issues on the factorization approach. PQCD results are compatible with present experimental data for charmless B-meson decays. We predict the possibility of large direct CP asymmetry in B0 → π+π (23 +7%) and B0K +π (− 17 ± 5%). We also investigate the branching ratios, CP asymmetry and isospin symmetry breaking in radiativeB(K*/ρ)γ decays.  相似文献   

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