Carlo Giunti
It is shown that neutrino mixing cannot explain the GSI time anomaly, refuting recent claims in this direction. Addendum 1: Remarks on arXiv:0801.1465. Addendum 2: Quantum effects in GSI nuclear decay.
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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.
The relationship between Breit-Wigner distribution as an underlying basis for decaying unstable quantum systems and GSI experiment (anomaly) has not been addressed properly in the literatures. We show that quantum beats can be obtained using a superposition of two Breit-Wigner distributions. This modified distribution can explain the GSI time anomaly with quantum beats resulting from the existence of two energy levels of the decaying ion.
Recently, an experiment at GSI Darmstadt has observed oscillating decay rates of heavy ions. Several controversial attempts have been made to explain this effect in terms of neutrino mixing. We briefly describe the experimental results, give an overview of the literature, and show that the effect cannot be due to neutrino mixing. If the effect survives, it could, however, be explained by hypothetical internal excitations of the mother ions (~ 10^(-15) eV).
We give comments on the recent paper by Giunti (Phys. Lett. B 665, 92 (2008), arXiv: 0805.0431 [hep-ph]) with a critique of our explanation of the experimentally observed periodic time-dependence of the interference term in the rate of the K-shell electron capture decay of the H-like ions 140Pr58+ and 142Pm60+ as a two-neutrino-flavour mixing. We show also that this phenomenon cannot be explained by a coherent mixing of two states of a mother ion as proposed by Giunti.
We investigate the influence of the strong Coulomb field of a heavy nucleus on massive neutrinos, produced in the K-shell electron capture (EC) decays of the H-like 140Pr58+ and 142Pm60+ ions. The corrections to the neutrino masses due to virtually produced charged lepton W-boson pairs in the strong Coulomb field of a nucleus with charge Ze are calculated and discussed with respect to their influence on the period of the time-modulation of the number of daughter ions, observed recently in the EC-decays of the H-like 140Pr58+ and 142Pm60+ ions at GSI in Darmstadt. These corrections explain the …
We propose a model in which a recently reported modulation in the decay of the hydrogenlike ions ${}^{140}$Pr$^{\, 58 +}$, ${}^{142}$Pm$^{\, 60 +}$ and ${}^{122}$I$^{\, 52 +}$ arises from the coupling of rotation to the spin of electron and nucleus. The model shows that the spin-spin coupling of electron and nucleus does not contribute to the modulation and predicts that the anomaly cannot be observed if the motion of the ions is rectilinear, or if the ions are stopped in a target. It also supports the notion that the modulation frequency is proportional to the inverse of the atomic mass.
The claims that the GSI time anomaly is due to the mixing of neutrinos in the final state of the observed electron-capture decays of hydrogen-like heavy ions are refuted with the help of an analogy with a double-slit experiment. It is a consequence of causality. It is shown that the GSI time anomaly may be caused by quantum beats due to the existence of two coherent energy levels of the decaying ion with an extremely small energy splitting (about $6\times10^{-16} \text{eV}$) and relative probabilities having a ratio of about 1/99.
According to GSI experiment Phys.Lett.B 664, 162 (2008), the rate of the daughter ion production by the K-shell electron capture (with neutrino emission) in H-like ions 142Pm, 140Pr and 152I is modulated with a period of 6 to 7 seconds. In PRL 103, 062502, 2009 by Ivanov and Kienle (also by Lipkin}) there is a claim that neutrino oscillations may explain this result. In arXiv:0811.2302 by Lambiase et al a different explanation is suggested which is based on the rotation of electron and nuclear spins. The aim of this Comment is to show why these explanations are not satisfactory and to discuss …
According to experimental data at GSI, the rates of the number of daughter ions, produced by the nuclear K-shell electron capture (EC) decays of the H-like 140Pr58+, 142Pm60+ and 122I52+ ions, are modulated in time with periods T_{EC} of the order of a few seconds, obeying an A-scaling T_{EC} = A/20 s, where A is the mass number of the mother nuclei, and with amplitudes a^{EC}_d ~ 0.21. In turn, the positron decay mode of the H-like 142Pm60+ ions showed no time modulation of the decay rates. As has been shown in Phys. Rev. Lett. 103, 062502 (2009) and Phys. Rev. Lett. 101, 182501 (2008), these…
With the help of an analogy with a double-slit experiment, it is shown that the standard method of calculation of the rate of an interaction process by adding the rates of production of all the allowed final states, regardless of a possible coherence among them, is correct. It is a consequence of causality. The claims that the GSI time anomaly is due to the mixing of neutrinos in the final state of the electron-capture process are refuted. It is shown that the GSI time anomaly may be due to quantum beats due to the existence of two coherent energy levels of the decaying ion with an extremely s…
We study a model for the "GSI anomaly" in which we obtain the time evolution of the population of parent and daughter particles directly in real time, considering explicitly the quantum entanglement between the daughter particle and neutrino mass eigenstates in the two-body decay. We confirm that the decay rate of the parent particle and the growth rate of the daughter particle do \emph{not} feature a time modulation from interference of neutrino mass eigenstates. The lack of interference is a consequence of the orthogonality of the mass eigenstates. This result also follows from the density m…
The claims that the GSI time anomaly is due to the mixing of neutrinos in the final state of the observed electron-capture processes are refuted. With the help of an analogy with a double-slit experiment, it is shown that the standard method of calculation of the rate of an interaction process by adding the rates of production of all the allowed final states, regardless of a possible coherence among them, is correct. It is a consequence of causality. It is shown that the GSI time anomaly may be caused by quantum beats due to the existence of two coherent energy levels of the decaying ion with …
It has been suggested that the reported temporal oscillations in the weak decay of H-like ions circulating in the GSI storage ring may be accounted for by interference between two different momentum components of the wave function of the parent ions. In that model, the interference is said to come about through coupling of those two momentum components to the two mass components in the wave function of the electron neutrino in the decayed state. I show here that quantum mechanics allows no such interference to contribute to the reported oscillation of the decay rate. The central issue is that …
We study the deviations from the usual exponential decay law for quantum mechanical systems. We show that simple and physically motivated deviations from the Breit-Wigner energy distribution of the unstable state are sufficient to generate peculiar deviations from the exponential decay law. Denoting with $p(t)$ the survival probability, its derivative $h(t)$ shows typically an oscillating behavior on top of the usual exponential function. We argue that this can be a viable explanation of the observed experimental results at GSI Darmstadt, where the function $h(t)$ has been experimentally measu…
In this talk, a short discussion of the GSI anomaly is given. We discuss the physics involved using a comparison with pion decay, and explain why the observed oscillations cannot be caused by standard neutrino mixing.
In this paper, I give a pedagogical discussion of the GSI anomaly. Using two different formulations, namely the intuitive Quantum Field Theory language of the second quantized picture as well as the language of amplitudes, I clear up the analogies and differences between the GSI anomaly and other processes (the Double Slit experiment using photons, $e^+ e^- \to μ^+ μ^-$ scattering, and charged pion decay). In both formulations, the conclusion is reached that the decay rate measured at GSI cannot oscillate if only Standard Model physics is involved and the initial hydrogen-like ion is no cohere…
It has been suggested that the temporal oscillations in the rate of decay of Pr ions reported in the GSI K-capture experiment arise from interference between different values of the momentum of the Pr ions. It is shown here that any such interference cannot contribute to the decay rate of those ions.
Taking the reported high-Q^2 anomaly at HERA as a signal of new physics, we show that several independent considerations point towards s-channel leptoquark production as the most attractive interpretation. We argue that even this option is highly constrained by flavor-changing processes: the couplings must be accurately diagonal in the quark and lepton mass eigenstate basis and should preserve individual quark and lepton family numbers. We propose a dynamical mechanism that might produce this pattern; it has distinctive experimental consequences.
I argue that ArXiv:1307.3251 is based on a misunderstanding of the role of Weyl transformations in local off-shell supersymmetry and what constitutes a true symmetry of the theory.
We investigate some aspects of anomaly cancellation realized by the subtraction of an anomaly pole, stressing on some of its properties in superspace. In a local formulation these subtractions can be described in terms of a physical scalar, an axion and related ghosts. They appear to be necessary for the unitarization of the theory in the ultraviolet, but they may generate an infrared instability of the corresponding effective action, signalled by ghost condensation. In particular the subtraction of the superanomaly multiplet by a pole in superspace is of dubious significance, due to the diffe…
We elucidate the physics underlying ``anomaly mediation'', giving several alternative derivations of the formulas for gaugino and scalar masses. We stress that this phenomenon is of a type familiar in field theory, and does not represent an anomaly, nor does it depend on supersymmetry breaking and its mediation. Analogous phenomena are common in QFT and this particular phenomenon occurs also in supersymmetric theories without gravity.
Owing to its lack of derivability, the dissipative anomaly operator appearing in the theory of turbulence without pressure recently proposed by Polyakov appears to be quite elusive. In particular, we give arguments that seem to lead to the conclusion that an anomaly in the first equation of the sequence of conservation laws cannot be {\it a priori} excluded.
In this paper we put on the test the new mechanism of gravitational origin recently put forth by Jaekel and Reynaud in order to explain the Pioneer anomaly in the framework of their post-Einsteinian metric extension of general relativity. According to such a proposal, the secular part of the anomalous acceleration experienced by the twin spacecraft of about 1 nm s^-2 could be caused by an extra-potential δΦ_P=c^2χr^2, with χ=4 10^-8 AU^-2, coming from the second sector of the considered model. When applied to the motion of the planets of the Solar System, it would induce anomalous secular peri…
Comment on "Chiral symmetry restoration, the eigenvalue density of the Dirac operator, and the axial U(1) anomaly at finite temperature"
本文质疑Aoki等人关于两味QCD在手征对称相中狄拉克谱密度和拓扑磁化率必须为零的证明，指出其关键步骤缺乏合理性。
Hints for the existence of a sterile neutrino at nuclear reactors are reexamined using two updated predictions for the fluxes of antineutrinos produced in fissions. These new predictions diverge in their preference for the rate deficit anomaly, relative to previous analyses, but the anomaly in the ratios of measured antineutrino spectra persists. We comment on upcoming experiments and their ability to probe the preferred region of the sterile-neutrino parameter space in the electron neutrino disappearance channel.
Recently, the ATLAS Collaboration recorded an interesting anomaly in diboson production with excesses at the diboson invariant mass around 2 TeV in boosted jets of all the $WZ$, $W^+ W^-$, and $ZZ$ channels. We offer a theoretical interpretation of the anomaly using a phenomenological right-handed model with extra $W'$ and $Z'$ bosons. Constraints from narrow total decay widths, dijet cross sections, and $W/Z + H$ production are taken into account. We also comment on a few other possibilities.
In this comment to the Nature paper of Bevan et al I point out that their interpretation of experimental data is based on a double counting of the `chiral anomaly' due to a vortex motion: using the calculation far away from the vortex core (Berry phase) to cancel the equivalent calculation at the core (spectral flow). The relaxation time approximation in force or momentum balance equation involved in their theory is also wrong, which has been rigorous proved in transport theory since 60's. Hence their affirmative conclusion is premature.
Comment on "Improved measurement of $η/η'$ mixing in $B_{(s)}^0\to J/ψη^{(\prime)}$ decays"
该评论指出，LHCb最新测得的$B_{(s)}^0\to J/ψη^{(\prime)}$衰变分支比比值，无需胶球-$η'$混合假设，只需纳入QCD $\u202eU_A(1)$反常增强的轻夸克湮灭效应贡献即可解释。
The Standard Model of electroweak interactions is shown to include a gauge theory for the observed scalar and pseudoscalar mesons. This is done by exploiting the consequences of embedding the SU(2)left X U(1) group into the chiral group of strong interactions and by considering explicitly the Higgs boson and its three companions inside the standard scalar 4-plet as composite. No extra scale of interaction is needed. Quantizing by the Feynman path integral reveals how, in the `Nambu Jona-Lasinio approximation', the quarks and the Higgs boson become unobservable, and the theory anomaly-free. Nev…
We develop the consequences of introducing a purely leptonic, lepton number violating non-standard interaction (NSI) and standard model neutrino mixing with a fourth, sterile neutrino in the analysis of short-baseline, neutrino experiments. We focus on the muon decay at rest (DAR) result from the Liquid Scintillation Neutrino Experiment (LSND) and the Karlsruhe and Rutherford Medium Energy Neutrino Experiment (KARMEN). We make a comprehensive analysis of lepton number violating, NSI effective operators and find nine that affect muon decay relevant to LSND results. Two of these preserve the sta…
The paper "Big Bang Nucleosynthesis and Active-Sterile Neutrino Mixing: Evidence for Maximal $ν_μ\leftrightarrow ν_τ$ Mixing in Super Kamiokande?" by X. Shi and G. M. Fuller (astro-ph/9810075) discusses the cosmological implications of the $ν_μ\to ν_s$ solution to the atmospheric neutrino anomaly. It incorrectly concludes that a lower bound on the $ν_τ$ mass of 15 eV is needed in order for the $ν_μ\to ν_s$ oscillations to be consistent with a Big Bang Nucleosynthesis upper bound on the effective number of flavours of 3.3. Since such a large $ν_τ$ mass is disfavoured from large scale structure …
We perform a systematic analysis of standard model extensions with an additional anomaly-free gauge $U(1)$ symmetry, to generate Dirac neutrino masses at one loop. Under such symmetry, standard model fields could either transform or be invariant, corresponding to an active $U(1)_X$ or a dark $U(1)_D$ symmetry, respectively. Having an anomaly-free symmetry imposes nontrivial conditions to the number and charges of the unavoidable new states. We perform an intensive scan, looking for non-anomalous solutions for given number of extra chiral fermions. In particular, we concentrate on solutions giv…
In this addendum to arXiv:1811.09603 we update our results including the recent measurement of ${\cal R}(D)$ and ${\cal R}(D^*)$ by the Belle collaboration: ${\cal R}(D)_{\rm Belle} = 0.307\pm0.037\pm0.016$ and ${\cal R}(D^*)_{\rm Belle}=0.283\pm0.018\pm0.014$, resulting in the new HFLAV fit result ${\cal R}(D) = {0.340\pm0.027 \pm 0.013}$, ${\cal R}(D^*) = {0.295\pm0.011 \pm 0.008 }$, exhibiting a $3.1\,σ$ tension with the Standard Model. We present the new fit results and update all figures, including the relevant new collider constraints. The updated prediction for ${\cal R}(Λ_c)$ from our …
Anomalies can be elegantly analyzed by means of the Dai-Freed theorem. In this framework it is natural to consider a refinement of traditional anomaly cancellation conditions, which sometimes leads to nontrivial extra constraints in the fermion spectrum. We analyze these more refined anomaly cancellation conditions in a variety of theories of physical interest, including the Standard Model and the $SU(5)$ and $Spin(10)$ GUTs, which we find to be anomaly free. Turning to discrete symmetries, we find that baryon triality has a $\mathbb{Z}_9$ anomaly that only cancels if the number of generations…
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