It is argued in [1] that when the strong coupling to the K Lambda channel is considered, Breit-Wigner mass of the lightest orbital excitation of the nucleon N(1535) shifts to a lower value. The new value turned out to be smaller than the mass of the lightest radial excitation N(1440), which effectively solved the long-standing problem of conventional constituent quark models. In this Comment we show that it is not the Breit-Wigner mass of N(1535) that is decreased, but its bare mass.
[1] B. C. Liu and B. S. Zou, Phys. Rev. Lett. 96, 042002 (2006).
It is pointed out that the Chiral Constituent Quark Model (CCQM) interactions that bind the H dibaryon and Lambda-Lambda-3H overbind Lambda-Lambda-6He by more than 4 MeV, thus outdating the CCQM in the strangeness S=-2 sector.
In this Reply, we respond to the above Comment. Our computation [Phys. Rev. D 91 (2015) 074512] only took into account pure QCD effects, arising from quark mass differences, so it is not surprising that there are discrepancies in isospin splittings and in the Sigma - Lambda mixing angle. We expect that these discrepancies will be smaller in a full calculation incorporating QED effects.
We comment on a recent suggestion by Amundson, Rosner, Worah and Wise to test the chirality of the $b$-quark decay coupling via polarized $Λ_b$ baryons produced in $e^+e^-\rightarrow Z\rightarrow Λ_b +X$. We study the effect of contributions from an amplitude in which a right-handed $b$ to $c$ current couples to a V-A lepton current.
Decays of the lightest neutralino are studied in R_p-violating models with operators lambda^{prime} L Q D^c and lambda L L E^c involving third-generation matter fields and with dominant lambda^{prime} and lambda couplings. Generalizations to decays of the lightest neutralino induced by subdominant lambda^{prime} and lambda couplings are straightforward. Decays with the top-quark among the particles produced are considered, in addition to those with an almost massless final state. Phenomenological analyses for examples of both classes of decays are presented. No specific assumption on the compo…
The strong coupling constants g_{K LAMBDA N} and g_{K SIGMA N} for the structure (sigma_{mu,nu} gamma_5) are calculated within light cone QCD sum rules. A comparison of our results on these couplings with predictions from traditional QCD sum rules is presented.
We analyze the one loop corrections to hadronic Z decays in an R-parity violating extension to the Minimal Supersymmetric Standard Model (MSSM). Performing a global fit to all the hadronic observables at the Z-peak, we obtain stringent constraints on the R-violating couplings constants lambda' and lambda''. As a result of the strong constraints from the b asymmetry parameters A_b and A_FB(b), we find that the couplings lambda'{i31}, lambda'{i32}, and lambda''{321} are ruled out at the 1 sigma level, and that lambda'{i33} and lambda''{33i} are ruled out at the 2 sigma level. We also obtain Baye…
The algorithm is described that enables one to perform an explicit summation of all the (π^2/ ln(Q^2/Lambda^2))^N corrections to α_s (Q^2) that appear owing to the analytic continuation from spacelike to timelike region of momentum transfer.
We study the coupling of the Lambda(1520)= Lambda* resonance to the \bar K* vector meson and nucleon. This coupling is not directly measured from the resonance decay, but is expected to be important in hyperon production reactions, in particular for the exotic Theta+ production. We compute the coupling in two different schemes, one in the chiral unitary model where the Lambda* is dominated by the quasibound state of mesons and baryons, and the other in the quark model where the resonance is a p-wave excitation in the three valence quarks. Although it is possible to construct both models such t…
We examine the radiative decays of the Lambda (1405) to octet baryons, Lambda + gamma and Sigma + gamma. In the limit of SU(3) symmetry the decay rates for these two modes are related, and we compute the leading correction to the relation in chiral perturbation theory. Such measurements will allow the sign of the strong coupling $g_{Λ^*}$ to be determined. The SU(3) violating radiative decay to the baryon decuplet Sigma* + gamma dominated by one-loop graphs is also discussed. Experiments planned for the Jefferson Laboratory should be able to measure some, if not all, of the processes considere…
Using the approximate flavor SU(3) symmetry of strong interactions, we argue for the existence of a new Lambda baryon with J^P=3/2^-, the mass around 1850 MeV, the total width of about 130 MeV, significant branching into the Sigma πand Sigma^{\ast} πstates and a vanishingly small coupling to the N {\bar K} state. This confirms quark model predictions suggesting a new Lambda baryon in the mass range between 1775 MeV and 1880 MeV with a very small coupling to the N {\bar K} state.
We present for the first time a self-contained calculation of the QCD running coupling at finite temperature and quark chemical potential, alpha_s(T, mu), based on a semiclassical background field method. The hard thermal/dense loop results on the Debye screening mass are recovered in a first approximation. The final result can be interpreted as the ordinary zero temperature running coupling, with momenta replaced by in-medium scales Lambda: at high density and zero temperature, the quark scale is set by Lambda ~ 24.4 mu. At high temperature and moderate densities, the quark in-medium scale re…
We calculate the isoscalar axial-vector coupling constants of the Lambda hyperon using the method of QCD sum rules. A determination of these coupling constants reveals the individual contributions of the u, d and the s quarks to the spin content of Lambda. Our results for the light-quark contributions are in agreement with those from experiment assuming flavor SU(3). We also find that the flavor-SU(3)-breaking effects are small and the contributions from the u and the d quarks to the Lambda polarization are negatively polarized as in the flavor-SU(3) limit.
Quark masses are included in the SCET Lagrangian. Treating the strange quark mass as order Lambda_{QCD}, we find that strange quark mass terms are suppressed in SCET1, but are leading order in SCET2. This is relevant for B decays to K^* and K. Strange quark mass effects in semileptonic and weak radiative form factors are studied. They give corrections to the form factors that are not suppressed by powers of the bottom quark mass, or, equivalently, by the large recoil energy of the final state meson, and and preserve the heavy to light form factor relations that follow from using the leading or…
We analyze the one loop corrections to leptonic W and Z decays in an R-parity violating extension to the Minimal Supersymmetric Standard Model (MSSM). We find that lepton universality violation in the Z line-shape variables alone would strengthen the bounds on the magnitudes of the lambda' couplings, but a global fit on all data leaves the bounds virtually unchanged at |lambda'_{33k}| < 0.42 and |lambda'_{23k}| < 0.50 at the 2 sigma level. Bounds from W decays are less stringent: |lambda'_{33k}| < 2.4 at 2 sigma, as a consequence of the weaker Fermilab experimental bounds on lepton universalit…
Inclusive Standard Model Higgs boson pair production at hadron colliders has the capability to determine the Higgs boson self-coupling, lambda. We present a detailed analysis of the gg\to HH\to (W^+W^-)(W^+W^-)\to (jjl^\pmν)(jj{l'}^\pmν) and gg\to HH\to (W^+W^-)(W^+W^-)\to (jjl^\pmν)({l'}^\pmν{l''}^\mpν) (l, {l'}, {l''}=e, μ) signal channels, and the relevant background processes, for the CERN Large Hadron Collider, and a future Very Large Hadron Collider operating at a center-of-mass energy of 200 TeV. We also derive quantitative sensitivity limits for lambda. We find that it should be possib…
A previous publication [H. S. Roising et al., Phys. Rev. Research 3, 033236 (2021)] involving the current authors pointed out a coupling between dark matter axions and ferroic orders in multiferroics. In this comment we argue that using this coupling for dark matter sensing is likely not feasible for the material class we considered, with present-day technologies and level of materials synthesis. The proposed effect (for QCD axions) is small and is overwhelmed by thermal noise. This finding means that likely materials for the proposed detection scheme would need to be found with significantly …
The coupling constants G_(K N Lambda) and G_(K N Sigma) are obtained from the Goldberger-Treiman relation in the strange channel with chiral symmetry breaking taken into account. The results, G_(K N Lambda)=-12.3+-1.2 and G_(K N Sigma)=5.5+-.5 come close to the SU(3) values.
By reanalyzing the influence of the anomalous $Z\bar t t$ couplings on the $Z\rightarrow b\bar b$ decay process, we pointed out the ambiguity in the conventional treatment of the effective Lagrangian approach, because of the possible existence of large contributions given by constant terms beyond the leading cutoff dependent term.
Lee and Weingarten have recently criticized our calculation of quarkonium and glueball scalars as being "incomplete" and "incorrect". Here we explain the relation of our calculations to full QCD.
Inclusive Standard Model Higgs boson pair production and subsequent decay to same-sign dileptons via weak gauge W bosons at the CERN Large Hadron Collider has the capability to determine the Higgs boson self-coupling, lambda. The large top quark mass limit is found not to be a good approximation for the signal if one wishes to utilize differential distributions in the analysis. We find that it should be possible at the LHC with design luminosity to establish that the Standard Model Higgs boson has a non-zero self-coupling and that lambda/lambda(SM) can be restricted to a range of 0--3.7 at 95%…
We calculate the complete order y^2 and y^4 terms of the 59 x 59 one-loop anomalous dimension matrix for the dimension-six operators of the Standard Model effective field theory, where y is a generic Yukawa coupling. These terms, together with the terms of order lambda, lambda^2 and lambda y^2 depending on the Standard Model Higgs self-coupling lambda which were calculated in a previous work, yield the complete one-loop anomalous dimension matrix in the limit of vanishing gauge couplings. The Yukawa contributions result in non-trivial flavor mixing in the various operator sectors of the Standa…
We propose an alternative unification scenario where the Higgs self-coupling (lambda) is unified with the electroweak SU(2)L x U(1)Y interactions at an intermediate scale MGH, lower than the GUT scale. In this model the SM remains valid up to this scale MGH, where the gauge and Higgs couplings satisfy the unification condition g1 = g2 = f(lambda). Two variants for this unification condition are discussed; scenario I is defined through the linear relation: g1 = g2 = k lambda(MGH), while scenario II assumes a quadratic relation: g1**2 = g2**2 = k lambda(MGH). An attractive feature of this class …
Jido, Oka and Hosaka have shown that the p-slash gamma_5 piece of the pion-to-vacuum correlator of two baryon interpolating fields vanishes in the soft-pion limit, as a consequence of chiral transformation properties of those fields. This is a statement about the particular combination of pion-baryon couplings and subtraction terms that corresponds to the chosen interpolating fields. It does not imply that the physical piNN* coupling of the N(1535) is suppressed.
The Fortran code NMHDECAY computes the masses, couplings and decay widths of all Higgs bosons of the NMSSM in terms of its parameters at the electroweak (SUSY breaking) scale: the Yukawa couplings lambda and kappa, the soft trilinear terms A_lambda and A_kappa, and tan(beta) and mu_eff = lambda*<S>. The computation of the spectrum includes leading two loop terms, electroweak corrections and propagator corrections. The computation of the decay widths is carried out as in HDECAY, but (for the moment) without three body decays. Each point in parameter space is checked against negative Higgs boson…
The latest measurements of the atomic level width in Sigma-hyperonic Pb atom offer the most accurate datum in the region of low-energy Sigma-hyperon physics. Atomic widths are due to the conversion of Sigma-nucleon into Lambda-nucleon. In high angular momentum states this conversion is dominated by the one-pion exchange. A joint analysis of the data of the scattering of negative-Sigma on proton converting into a Lambda and a neutron and of the atomic widths allows to extract a pseudovector pion-hyperon-Sigma coupling constant of 0.048 with a statistical error of +-0.005 and a systematic one of…
Motivated by recent results on charmed baryons from CLEO and FOCUS, we reexamine the couplings of the orbitally excited charmed baryons. Due to its proximity to the [Sigma_c pi] threshold, the strong decays of the Lambda_c(2593) are sensitive to finite width effects. This distorts the shape of the invariant mass spectrum in Lambda_{c1}-> Lambda_c pi^+pi^- from a simple Breit-Wigner resonance, which has implications for the experimental extraction of the Lambda_c(2593) mass and couplings. We perform a fit to unpublished CLEO data which gives M(Lambda_c(2593)) - M(Lambda_c) = 305.6 +- 0.3 MeV an…
Calculations of deep inelastic processes (DIS) to next-to-next to leading order are discussed. Fitting $ep$ experiment in the range $2.5\leq Q^2\leq 230 GeV^2$, we find the coupling $α_s(M_Z^2)=0.1163\pm0.0023$. We also get the gluon density $xG(x,Q^2\simeq 10 GeV^2)=0.51 x^{-0.44}(1-x)^{8.1}$, and negative evidence for the existence of light gluinos
We calculate the order λ, λ^2 and λy^2 terms of the 59 x 59 one-loop anomalous dimension matrix of dimension-six operators, where λand y are the Standard Model Higgs self-coupling and a generic Yukawa coupling, respectively. The dimension-six operators modify the running of the Standard Model parameters themselves, and we compute the complete one-loop result for this. We discuss how there is mixing between operators for which no direct one-particle-irreducible diagram exists, due to operator replacements by the equations of motion.
In this comment, we propose possible errors in constructing the continuum contribution in the sum rule studied by M. C. Birse and B. Krippa, Phys. Rev. C. {\bf 54} (1996) 3240.
Previous top-down studies of jet stopping in strongly-coupled QCD-like plasmas with gravity duals have been in the infinite 't Hooft coupling limit lambda -> infinity. They have found that, though a wide range of jet stopping distances are possible depending on initial conditions, the maximum jet stopping distance l_max scales with energy as E^(1/3) at large energy. But it has always been unclear whether the large-coupling and high-energy limits commute. In this paper, we use the string alpha' expansion in AdS-CFT to study the corrections to the lambda=infinity result in powers of 1/lambda. Fo…
The quark-meson coupling (QMC) model, which has been successfully used to describe the properties of both infinite nuclear matter and finite nuclei, is applied to a systematic study of $Λ, Σ$ and $Ξ$ hypernuclei. Assumptions made in the present study are, (i) the (self-consistent) exchanged scalar, and vector, mesons couple only to the u and d quarks, and (ii) an SU(6) valence quark model for the bound nucleons and hyperon. The model automatically leads to a very weak spin-orbit interaction for the $Λ$ in a hypernucleus. Effects of the Pauli blocking at the quark level, particularly in the ope…
We investigate a model of R-parity violating (RPV) supersymmetry in which the right-handed sbottom is the lightest supersymmetric particle, and a baryon number violating coupling involving a top is the only non-negligible RPV coupling. This model evades proton decay and flavour constraints. We consider in turn each of the couplings lambda"_{313} and lambda"_{323} as the only non-negligible RPV coupling, and we recast two recent Large Hadron Collider (LHC) measurements and searches (CMS top transverse momentum p_T(t) spectrum and ATLAS multiple jet resonance search) in the form of constraints o…
We argue that, when coupled to Einstein's theory of gravity, the Yukawa theory may solve the cosmological constant problem in the following sense: The radiative corrections of fermions generate an effective potential for the scalar field, such that the effective cosmological term Lambda_eff is dynamically driven to zero. Thence, for any initial positive cosmological constant Lambda_0, Lambda_eff = 0 is an attractor of the semiclassical Einstein theory coupled to fermionic and scalar matter fields. When the initial cosmological term is negative, Lambda_eff=Lambda_0 does not change. Next we argu…
In this paper we present for the first time a detailed Monte Carlo study of measuring WZGamma production with pure leptonic decays and probing anomalous quartic gauge-boson WWZGamma couplings at the sqrt(s) = 14 TeV LHC, with parton shower and detector simulation effects taken into account. We find that with an integrated luminosity of 100 fb-1 and proper selection cuts, the Standard Model WZGamma signal significance can be improved to as much as 3 sigma. After reviewing previous parametrization on anomalous WWZGamma couplings (see e.g.an/Lambda^2 or k2m/Lambda^2 as shown in Ref. [17]), we pro…
We present a non-perturbative computation of the running of the coupling alpha_s in QCD with two flavours of dynamical fermions in the Schroedinger functional scheme. We improve our previous results by a reliable continuum extrapolation. The Lambda-parameter characterizing the high-energy running is related to the value of the coupling at low energy in the continuum limit. An estimate of Lambda*r_0 is given using large-volume data with lattice spacings a from 0.07 fm to 0.1 fm. It translates into Lambda_{MSbar}^{(2)}=245(16)(16) MeV [assuming r_0=0.5 fm]. The last step still has to be improved…
The authors of ref. Phys.Rev. D94 (2016) no.1, 014502 reported about a careful analysis of the impact of lattice artifacts on the $SU(3)$ gauge-field propagators. In particular, they found that the low-momentum behavior of the renormalized propagators depends on the lattice bare coupling and interpreted this fact as the result of it being affected by finite lattice spacing artifacts. We do not share this interpretation and present here a different and more suitable explanation for these results.
We argue that future e^{+} e^{-} linear colliders can produce many sneutrinos if lepton-number violating couplings lambda_{1j1} exist and enough beam polarization is obtained. The terms lambda_{ijk} L_{i} L_{j} E_{k}^{c} are allowed in a discrete Z_{3}-symmetry which is used to forbid rapid proton decay, and it is worthwhile to consider the possibility of the existence of such terms and their resultant. We study the process e^{+}e^{-} -> sneutrino -> e^{+} e^{-} in detail, and show that if such resonance is not found, lepton-number violating couplings lambda_{1j1}, will be strongly constrained…
The HypHI Collaboration at GSI argued recently for a (Lambda-n-n) bound state from the observation of its two-body (t + pi-) weak-decay mode. We derive constraints from several hypernuclear systems, in particular from the A=4 hypernuclei with full consideration of (Lambda N <--> Sigma N) coupling, to rule out a bound (Lambda-n-n).
In a recent study on monopole production [Eur. Phys. J. C (2018) 78: 966], Baines et al added the potential of a magnetic dipole to the Wu-Yang potentials for the Dirac monopole and claimed that this modified Wu-Yang configuration does not affect the Dirac quantisation condition. In this comment, we argue that their claim is incorrect by showing that their modified Wu-Yang configuration leads to an infinite number of quantisation conditions. In their study, they also incorrectly identified the magnetic field of the monopole with the magnetic field of the Dirac string and its attached magnetic …
Critical slowing down of the relaxation of the order parameter is relevant both in early the universe and in ultrarelativistic heavy ion collisions. We study the relaxation rate of the order parameter in an O(N) scalar theory near the critical point to model the non-equilibrium dynamics of critical fluctuations near the chiral phase transition.A lowest order perturbative calculation (two loops in the coupling lambda) reveals the breakdown of perturbation theory for long-wavelength fluctuations in the critical region and the emergence of a hierarchy of scales with hard q>T, semisoft T >> q >> l…
We study the photoproduction of the ^12{_Lambda}B hypernucleus within a fully covariant effective Lagrangian based model, employing Lambda bound state spinors derived from the latest quark-meson coupling model. The kaon production vertex is described via creation, propagation and decay of N*(1650), N*(1710), and N*(1720) intermediate baryonic resonant states in the initial collision of the photon with a target proton in the incident channel. The parameters of the resonance vertices are fixed by describing the total and differential cross section data on the elementary gamma (p, K+) Lambda reac…
A recently proposed solution of the `GSI anomaly' by spin precession of the decaying heavy ions in the magnetic field that controls their circular motion at the GSI storage ring [G. Lambiase, G. Papini, G. Scarpetta, PLB 718 (2013) 998, Ann. Phys. 332 (2013) 143] is dubious: the uncertainty in the computed electron-capture decay-rate modulation frequency is at least of order 10E(7) Hz, by far exceeding the 1 Hz modulation frequency reported in the GSI experiment.
