Wed·Jul 11, 2018Wednesday·July 11, 2018

1. 01*

   A few moments to diagnose fast flavor conversions of supernova neutrinos

   Basudeb Dasgupta (Tata Inst.)🇮🇳 · Alessandro Mirizzi (Bari Univ. and INFN Bari)🇮🇹 · Manibrata Sen (Tata Inst.)🇮🇳

   Neutrinos emitted from a supernova may undergo flavor conversions almost immediately above the core, with possible consequences for supernova dynamics and nucleosynthesis. However, the precise conditions for such fast conversions can be difficult to compute and require knowledge of the full angular distribution of the flavor-dependent neutrino fluxes, that is not available in typical supernova simulations. In this paper, we show that the overall flavor evolution is qualitatively similar to the growth of a so-called `zero mode', determined by the background matter and neutrino densities, which can be reliably predicted using only the second angular moments of the electron lepton number distribution, i.e., the difference in the angular distributions of ${\nu }_e$ and ${\bar{\nu }}_e$ fluxes. We propose that this zero mode, which neither requires computing the full Green's function nor a detailed knowledge of the angular distributions, may be useful for a preliminary diagnosis of possible fast flavor conversions in supernova simulations with modestly resolved angular distributions

   hep-phastro-ph.COastro-ph.HEastro-ph.SRPRD(2018)·82 citations
2. 02*

   The Ratio $\mathcal{R}(D)$ and the $D$-meson Distribution Amplitude

   Tao Zhong🇨🇳 · Yi Zhang🇨🇳 · Xing-Gang Wu🇨🇳 · Hai-Bing Fu🇨🇳 · Tao Huang🇨🇳

   In this paper, we calculate the $B\to D$ transition form factors (TFFs) within the light-cone sum rules (LCSR) and predict the ratio $\mathcal{R}(D)$. More accurate $D$-meson distribution amplitudes (DAs) are essential to get a more accurate theoretical prediction. We construct a new model for the twist-3 DAs ${\varphi }_{3;D}^p$ and ${\varphi }_{3;D}^{\sigma }$ based on the QCD sum rules under the background field theory for their moments as we have done for constructing the leading-twist DA ${\varphi }_{2;D}$. As an application, we observe that the twist-3 contributions are sizable in whole $q^2$-region. Taking the twist-2 and twist-3 DAs into consideration, we obtain $f_{+,0}^{B\to D}(0)=0.659_{-0.032}^{+0.029}$. As a combination of the Lattice QCD and the QCD LCSR predictions on the TFFs $f_{+,0}^{B\to D}(q^2)$, we predict $\mathcal{R}(D)=0.320_{-0.021}^{+0.018}$, which improves is about $1.5\sigma$ deviation from the HFAG average of the Belle and BABAR data. At present the data are still of large errors, and we need further accurate measurements of the experiment to confirm whether there is signal of new physics from the ratio $\mathcal{R}(D)$.

   hep-phEPJC(2018)·24 citations
3. 03*

   Bound on a flux of ultra-high energy neutrinos in a scenario with extra dimensions

   M.O. Astashenkov🇷🇺 · A.V. Kisselev🇷🇺

   Assuming that a single-flavor diffuse neutrino flux dN_nu/dE_nu is equal to k*E_nu^(-2) in the energy range 10^(17) eV - 2.5*10^(19) eV, an upper bound on k is calculated in the ADD model as a function of the number of extra dimensions n and gravity scale M_D. An expected number of neutrino induced events at the Surface Detector array of the Pierre Auger Observatory is estimated.

   hep-phastro-ph.HEEPJ Web Conf.(2018)·0 citations
4. 04*

   The light CP-even MSSM Higgs mass resummed to fourth logarithmic order

   R.V. Harlander🇩🇪 · J. Klappert🇩🇪 · A.D. Ochoa🇩🇪 · A. Voigt🇩🇪

   We present the calculation of the light neutral CP-even Higgs mass in the MSSM for a heavy SUSY spectrum by resumming enhanced terms through fourth logarithmic order (N${}^3$LL), keeping terms of leading order in the top Yukawa coupling ${\alpha }_t$, and NNLO in the strong coupling ${\alpha }_s$. To this goal, the three-loop matching coefficient for the quartic Higgs coupling of the SM to the MSSM is derived to order ${\alpha }_t^2{\alpha }_s^2$ by comparing the perturbative EFT to the fixed-order expression for the Higgs mass. The new matching coefficient is made available through an updated version of the program Himalaya. Numerical effects of the higher-order resummation are studied using specific examples, and sources of theoretical uncertainty on this result are discussed.

   hep-phEPJC(2018)·44 citations
5. 05*

   The two-real-singlet Dark Matter model

   A. Arhrib🇲🇦 · M. Maniatis🇨🇱

   We revisit a Dark Matter model with an extension of the Standard Model with two real singlets $\chi$ and $\eta$ obeying a $Z_2\otimes Z_2^{\prime }$ symmetry, where $Z_2^{\prime }$ is broken spontaneously. While $\chi$ serves as a stable Dark Matter candidate providing the relic density, the real $\eta$ field plays the role of a light mediator. We study the viability of this model with respect to Dark Matter self-interactions which may explain the density profiles observed in dwarf galaxies up to scales of the size of our Milky Way. Moreover, the Standard Model-like Higgs boson of the model has a tiny mixing with the mediator field and appears to be consistent with current LHC data. In this rather minimal extension of the Standard Model the mediator $\eta$ decays naturally into Majorana neutrinos neither disturbing standard big bang nucleosynthesis nor cosmic microwave background observations.

   hep-phPLB(2019)·9 citations
6. 06*

   Effective operators in $t$-channel single top production and decay

   M. de Beurs🇳🇱 · E. Laenen🇳🇱 · M. Vreeswijk🇳🇱 · E. Vryonidou🇨🇭

   The production of a single top quark in the $t$-channel and its subsequent decay is studied at NLO accuracy in QCD, augmented with the relevant dimension-6 effective operators from the Standard Model Effective Theory. We examine various kinematic and angular distributions for proton-proton collisions at the LHC at 13 TeV, in order to assess the sensitivity to these operators, both with and without the top quark narrow width approximation. Our results will be helpful when devising strategies to establish bounds on their coefficients, including the amount of CP violation of the weak dipole operator.

   hep-phEPJC(2018)·41 citations
7. 07*

   From elliptic curves to Feynman integrals

   Luise Adams🇩🇪 · Ekta Chaubey🇩🇪 · Stefan Weinzierl🇩🇪

   In this talk we discuss Feynman integrals which are related to elliptic curves. We show with the help of an explicit example that in the set of master integrals more than one elliptic curve may occur. The technique of maximal cuts is a useful tool to identify the elliptic curves. By a suitable transformation of the master integrals the system of differential equations for our example can be brought into a form linear in $\epsilon$, where the ${\epsilon }^0$-term is strictly lower-triangular. This system is easily solved in terms of iterated integrals.

   hep-phhep-thPoS(2018)·7 citations
8. 08*

   Safe Pati-Salam

   Emiliano Molinaro🇩🇰 · Francesco Sannino🇩🇰 · Zhi-Wei Wang🇩🇰

   We provide an asymptotically safe Pati-Salam embedding of the Standard Model. Safety is achieved by adding to the theory gauged vector-like fermions and by employing recently developed large number-of-flavor techniques and results. We show that the gauge, scalar quartic and Yukawa couplings achieve an interacting ultraviolet fixed point below the Planck scale. The minimal model is a relevant example of a Standard Model extension in which unification of all type of couplings occurs because of a dynamical principle, i.e. the presence of an ultraviolet fixed point. This extension differs from the usual Grand Unified Theories scenario in which only gauge couplings unify and become free with the remaining couplings left unsafe. We find renormalization group flow solutions that match the Standard Model couplings values at low energies allowing for realistic safe extensions of the Standard Model.

   hep-phhep-lathep-thPRD(2018)·37 citations
9. 09*

   Deep Learning as a Parton Shower

   James William Monk🇩🇰

   We make the connection between certain deep learning architectures and the renormalisation group explicit in the context of QCD by using a deep learning network to construct a toy parton shower model. The model aims to describe proton-proton collisions at the Large Hadron Collider. A convolutional autoencoder learns a set of kernels that efficiently encode the behaviour of fully showered QCD collision events. The network is structured recursively so as to ensure self-similarity, and the number of trained network parameters is low. Randomness is introduced via a novel custom masking layer, which also preserves existing parton splittings by using layer-skipping connections. By applying a shower merging procedure, the network can be evaluated on unshowered events produced by a matrix element calculation. The trained network behaves as a parton shower that qualitatively reproduces jet-based observables.

   hep-phJHEP(2018)·61 citations
10. 10*

    Decoherence-effects in the neutrino-mixing mechanism: active and sterile neutrinos in the three flavor scheme

    M.Mosquera🇦🇷 · O. Civitarese🇦🇷

    In this work we analyze the effects of quantum decoherence upon the precession of the neutrino polarization vector in a supernovae-like environment. In order to perform the study we have determined the time-dependence of the polarization vector by solving the equation of motion for different neutrino-mixing schemes. The results of the calculations show that the onset of decoherence depends strongly on the parameters of the adopted mixing scheme. As examples we have considered : a) the mixing between active neutrinos and b) the mixing between active end sterile neutrinos.

    hep-phastro-ph.HE1 citation
11. 11*

    Infrared sensitivity of single jet inclusive production at hadron colliders

    James Currie🇬🇧 · Aude Gehrmann-De Ridder🇨🇭 · Thomas Gehrmann🇨🇭 · E.W.N. Glover🇬🇧 · Alexander Huss🇨🇭 · Joao Pires🇵🇹

    Jet production at hadron colliders is a benchmark process to probe the dynamics of the strong interaction and the structure of the colliding hadrons. One of the most basic jet production observables is the single jet inclusive cross section, which is obtained by summing all jets that are observed in an event. Our recent computation of next-to-next-to-leading order (NNLO) QCD contributions to single jet inclusive observables uncovered large corrections in certain kinematical regions, which also resulted in a sizeable ambiguity on the appropriate choice of renormalization and factorization scales. We now perform a detailed investigation of the infrared sensitivity of the different ingredients to the single jet inclusive cross section. We show that the contribution from the second jet, ordered in transverse momentum $p_T$, in the event is particularly sensitive to higher order effects due to implicit restrictions on its kinematics. By investigating the second-jet transverse momentum distribution, we identify large-scale cancellations between different kinematical event configurations, which are aggravated by certain types of scale choice. Taking perturbative convergence and stability as selection criteria enables us to single out the total partonic transverse energy ${\hat{H}}_T$ and twice the individual jet transverse momentum $2p_T$ (with which ${\hat{H}}_T$ coincides in Born kinematics) as the most appropriate scales in the perturbative description of single jet inclusive production.

    hep-phhep-exJHEP(2018)·88 citations
12. 12*

    Soft gluon resummation for Higgs boson pair production including finite Mt effects

    Daniel de Florian🇦🇷 · Javier Mazzitelli🇨🇭

    We perform the all orders resummation of threshold enhanced contributions for the Higgs boson pair production cross section via gluon fusion, including finite top quark mass ($M_t$) effects. We present results for the total cross section and Higgs pair invariant mass ($M_{hh}$) distribution. We obtain results at next-to-leading logarithmic accuracy (NLL) which retain the full $M_t$ dependence, and are matched to the full next-to-leading order (NLO) prediction. Our NLL+NLO results represent the most advanced prediction with full $M_t$ dependence for this process, and produce an increase of about 4% in the total cross section with respect to the NLO result for LHC energies, and for a central scale ${\mu }_0=M_{hh}/2$. We also consistently combine the full NLL with the next-to-next-to-leading logarithmically (NNLL) accurate resummation computed in the Born-improved large-$M_t$ limit, and match it to the next-to-next-to-leading order approximation of Ref. \cite{Grazzini:2018bsd}, so called NNLO_FTa. We find that the resummation effects are very small at NNLL for ${\mu }_0=M_{hh}/2$, in particular below 1% at 13 TeV, indicating that the perturbative expansion is under control. In all cases the resummation effects are found to be substantially larger for the central scale ${\mu }_0=M_{hh}$, resulting in a more stable cross section with respect to scale variations than the fixed order calculation.

    hep-phJHEP(2018)·39 citations
13. 13*

    Role of a four-quark and a glueball state in pion-pion and pion-nucleon scattering

    Phillip Lakaschus🇩🇪 · Justin L.P. Mauldin🇩🇪 · Francesco Giacosa🇵🇱 · Dirk H. Rischke🇩🇪

    We consider the two-flavor version of the extended linear sigma model (eLSM), which contains (pseudo)scalar and (axial-)vector quark-antiquark mesons, a scalar glueball (predominantly corresponding to $f_0(1710)$), as well as the nucleon and its chiral partner. We extend this model by the additional light scalar meson $f_0(500)$, predominantly a putative four-quark state. We investigate various interaction terms of the four-quark and glueball states with the other particles, some of which preserve and some of which explicitly break the $U(1{)}_{\text{A}}$ symmetry. We test our model by performing a global fit to masses and decay widths of the scalar resonances and pion-pion scattering lengths. We also discuss the influence of the scalar four-quark state and the glueball on the baryon sector by evaluating pion-nucleon scattering parameters. We find that the inclusion of $f_0(500)$ improves the description of pion-pion and pion-nucleon scattering lengths.

    hep-phPRC(2019)·12 citations
14. 14*

    A Bayesian analysis of sneutrino DM in the NMSSM with Type-I seesaw mechanism

    Junjie Cao🇨🇳 · Jie Li🇨🇳 · Yusi Pan🇨🇳 · Liangliang Shang🇨🇳 · Yuanfang Yue🇨🇳 · Di Zhang🇨🇳

    In the Next-to-Minimal Supersymmetric Standard Model (NMSSM) with extra heavy neutrino superfields, neutrino may acquire its mass via a seesaw mechanism and sneutrino may act as a viable dark matter (DM) candidate. Given the strong tension between the naturalness for $Z$ boson mass and the DM direct detection experiments for customary neutralino DM candidate, we augment the NMSSM with Type-I seesaw mechanism, which is the simplest extension of the theory to predict neutrino mass, and study the scenarios of sneutrino DM. We construct likelihood function with LHC Higgs data, B-physics measurements, DM relic density and its direct and indirect search limits, and perform a comprehensive scan over the parameter space of the theory by Nested Sampling method. We adopt both Bayesian and frequentist statistical quantities to illustrate the favored parameter space of the scenarios, the DM annihilation mechanism as well as the features of DM-nucleon scattering. We find that the scenarios are viable over broad parameter regions, especially the Higgsino mass $\mu$ can be below about $250\mathrm{GeV}$ for a significant part of the region, which predicts $Z$ boson mass in a natural way. We also find that the DM usually co-annihilated with the Higgsinos to get the measured relic density, and consequently the DM-nucleon scattering rate is naturally suppressed to coincide with the recent XENON-1T results even for light Higgsinos. Other issues, such as the LHC search for the Higgsinos, are also addressed.

    hep-phPRD(2019)·26 citations
15. 15*

    Detecting Dark Blobs

    Dorota M Grabowska🇺🇸 · Tom Melia🇯🇵 · Surjeet Rajendran🇺🇸

    Current dark matter detection strategies are based on the assumption that the dark matter is a gas of non-interacting particles with a reasonably large number density. This picture is dramatically altered if there are significant self interactions within the dark sector, potentially resulting in the coalescence of dark matter particles into large composite blobs. The low number density of these blobs necessitates new detector strategies. We study cosmological, astrophysical and direct detection bounds on this scenario and identify experimentally accessible parameter space. The enhanced interaction between large composite states and the standard model allows searches for such composite blobs using existing experimental techniques. This includes the detection of scintillation in MACRO, XENON and LUX, heat in calorimeters such as CDMS, acceleration and strain in gravitational wave detectors such as LIGO and AGIS, and spin precession in CASPEr. These searches leverage the fact that the transit of the dark matter occurs at a speed ~220 km/s, well separated from relativistic and terrestrial sources of noise. They can be searched for either through modifications to the data analysis protocol or relatively straightforward adjustments to the operating conditions of these experiments.

    hep-phastro-ph.COhep-thPRD(2018)·91 citations
16. 16*

    Exploring Leptophilic Dark Matter with NA64-$\mu$

    Chien-Yi Chen🇨🇦 · Jonathan Kozaczuk🇺🇸 · Yi-Ming Zhong🇺🇸

    We investigate the prospects for detecting light leptophilic dark sectors with a missing-momentum experiment at NA64 running in muon mode. In particular, we consider models in which dark matter connects to the visible sector through a lepton- or muon-specific scalar mediator. These scalars can also account for the $\sim 3.5\sigma$ discrepancy between the measured and predicted values of $(g-2{)}_{\mu }$ . We emphasize the complementarity between NA64-$\mu$ and other terrestrial and astrophysical probes.

    hep-phhep-exJHEP(2018)·65 citations
17. 17*

    Quark branching in QCD matter to any order in opacity beyond the soft gluon emission limit

    Matthew D. Sievert🇺🇸 · Ivan Vitev🇺🇸

    Cold nuclear matter effects in reactions with nuclei at a future electron-ion collider (EIC) lead to a modification of semi-inclusive hadron production, jet cross sections, and jet substructure when compared to the vacuum. At leading order in the strong coupling, a jet produced at an EIC is initiated as an energetic quark, and the process of this quark splitting into a quark-gluon system underlies experimental observables. The spectrum of gluons associated with the branching of this quark jet is heavily modified by multiple scattering in a medium, allowing jet cross sections and jet substructure to be used as a probe of the medium's properties. We present a formalism that allows us to compute the gluon spectrum of a quark jet to an arbitrary order in opacity, the average number of scatterings in the medium. This calculation goes beyond the simplifying limit in which the gluon radiation is soft and can be interpreted as energy loss of the quark, and it significantly extends previous work which computes the full gluon spectrum only to first order in opacity. The theoretical framework demonstrated here applies equally well to light parton and heavy quark branching, and is easily generalizable to all in-medium splitting processes.

    hep-phPRD(2018)·73 citations
18. 18*

    Vacuum birefringence in the head-on collision of XFEL and optical high-intensity laser pulses

    Felix Karbstein🇩🇪

    The focus of this article is on providing compact analytical expressions for the differential number of polarization flipped signal photons constituting the signal of vacuum birefringence in the head-on collision of x-ray free electron (XFEL) and optical high-intensity laser pulses. Our results allow for unprecedented insights into the scaling of the effect with the waists and pulse durations of both laser beams, the Rayleigh range of the high-intensity beam, as well as transverse and longitudinal offsets. They account for the decay of the differential number of signal photons in the far-field as a function of the azimuthal angle measured relative to the beam axis of the probe beam in forward direction, typically neglected by conventional approximations. Moreover, they even allow us to extract an analytical expression for the angular divergence of the perpendicularly polarized signal photons. We expect our formulas to be very useful for the planning and optimization of experimental scenarios aiming at the detection of vacuum birefringence in XFEL/high-intensity laser setups, such as the one put forward at the Helmholtz International Beamline for Extreme Fields (HIBEF) at the European XFEL.

    ↳ quant-phhep-phhep-thPRD(2018)·46 citations
19. 19*

    Radiative effects on false vacuum decay in Higgs-Yukawa theory

    Wen-Yuan Ai🇩🇪 · Bjorn Garbrecht🇩🇪 · Peter Millington🇬🇧

    We derive fermionic Green's functions in the background of the Euclidean solitons describing false vacuum decay in a prototypal Higgs-Yukawa theory. In combination with appropriate counterterms for the masses, couplings and wave-function normalization, these can be used to calculate radiative corrections to the soliton solutions and transition rates that fully account for the inhomogeneous background provided by the nucleated bubble. We apply this approach to the archetypal example of transitions between the quasi-degenerate vacua of a massive scalar field with a quartic self-interaction. The effect of fermion loops is compared with those from additional scalar fields, and the loop effects accounting for the spacetime inhomogeneity of the tunneling configuration are compared with those where gradients are neglected. We find that scalar loops lead to an enhancement of the decay rate, whereas fermion loops lead to a suppression. These effects get relatively amplified by a perturbatively small factor when gradients are accounted for. In addition, we observe that the radiative corrections to the solitonic field profiles are smoother when the gradients are included. The method presented here for computing fermionic radiative corrections should be applicable beyond the archetypal example of vacuum decay. In particular, we work out methods that are suitable for calculations in the thin-wall limit, as well as others that take account of the full spherical symmetry of the solution. For the latter case, we construct the Green's functions based on spin hyperspherical harmonics, which are eigenfunctions of the appropriate angular momentum operators that commute with the Dirac operator in the solitonic background.

    ↳ hep-thhep-phPRD(2018)·27 citations
20. 20*

    Extraction of the Specific Shear Viscosity of Hot Hadron Gas

    Zhidong Yang🇺🇸 · Rainer J. Fries🇺🇸

    We extract the specific shear viscosity $\eta /s$ of nuclear matter for various temperatures and chemical potentials in the hadronic phase using data taken in high energy nuclear collisions. We use a blastwave parameterization of the final state of nuclear collisions, including non-equilibrium deformations of particle distributions due to shear stress in the Navier-Stokes approximation. We fit spectra and elliptic flow of identified hadrons for a variety of collision energies and impact parameters at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). The systems analyzed cover a temperature range from about 110 to 140 MeV and vary in their chemical potentials for stable hadrons. We attempt to assign meaningful systematic uncertainties to our results. This work is complementary to efforts using viscous fluid dynamics to extract the specific shear viscosity of quark gluon plasma at higher temperatures. We put our work in context with existing theoretical calculations of the specific shear viscosity.

    ↳ nucl-thhep-phnucl-ex4 citations
21. 21*

    First measurement of $e^{+}{e}^{-}\to p{K}_S^0\bar{n}{K}^{-}+c.c.$ above open charm threshold

    BESIII Collaboration: M. Ablikim · M. N. Achasov · S. Ahmed · M. Albrecht · M. Alekseev · A. Amoroso · F. F. An · Q. An · J. Z. Bai · Y. Bai · O. Bakina · R. Baldini Ferroli and 426 other authors

    The process $e^{+}{e}^{-}\to p{K}_S^0\bar{n}{K}^{-}+c.c.$ and its intermediate processes are studied for the first time, using data samples collected with the BESIII detector at BEPCII at center-of-mass energies of 3.773, 4.008, 4.226, 4.258, 4.358, 4.416, and 4.600 GeV, with a total integrated luminosity of 7.4 fb${}^{-1}$. The Born cross section of $e^{+}{e}^{-}\to p{K}_S^0\bar{n}{K}^{-}+c.c.$ is measured at each center-of-mass energy, but no significant resonant structure in the measured cross-section line shape between 3.773 and 4.600 GeV is observed. No evident structure is detected in the $p{K}^{-}$, $n{K}_S^0$, $p{K}_S^0$, $n{K}^{+}$, $p\bar{n}$, or $K_S^0{K}^{-}$ invariant mass distributions except for $\Lambda (1520)$. The Born cross sections of $e^{+}{e}^{-}\to \Lambda (1520)\bar{n}{K}_S^0+c.c.$ and $e^{+}{e}^{-}\to \Lambda (1520)\bar{p}{K}^{+}+c.c.$ are measured, and the 90\% confidence level upper limits on the Born cross sections of $e^{+}{e}^{-}\to \Lambda (1520)\bar{\Lambda }(1520)$ are determined at the seven center-of-mass energies.

    ↳ hep-exhep-phPRD(2018)·14 citations
22. 22*

    Reaching supercritical field strengths with intense lasers

    T. G. Blackburn🇸🇪 · A. Ilderton🇬🇧 · M. Marklund🇸🇪 · C. P. Ridgers🇬🇧

    It is conjectured that all perturbative approaches to quantum electrodynamics (QED) break down in the collision of a high-energy electron beam with an intense laser, when the laser fields are boosted to `supercritical' strengths far greater than the critical field of QED. As field strengths increase toward this regime, cascades of photon emission and electron-positron pair creation are expected, as well as the onset of substantial radiative corrections. Here we identify the important role played by the collision angle in mitigating energy losses to photon emission that would otherwise prevent the electrons reaching the supercritical regime. We show that a collision between an electron beam with energy in the tens of GeV and a laser pulse of intensity $10^{24}\text{W}{\text{cm}}^{-2}$ at oblique, or even normal, incidence is a viable platform for studying the breakdown of perturbative strong-field QED. Our results have implications for the design of near-term experiments as they predict that certain quantum effects are enhanced at oblique incidence.

    ↳ physics.plasm-phhep-phNew J.Phys.(2019)·61 citations
23. 23*

    Lattice QCD: Flavor Physics and Spectroscopy

    Takashi Kaneko🇯🇵

    We review highlights of recent results on the hadron spectrum and flavor physics from lattice QCD. We also discuss recent rapid progress on the muon anomalous magnetic moment.

    ↳ hep-lathep-exhep-ph2 citations
24. 24*

    Problems with variable Hilbert space in quantum mechanics

    I. F. Ginzburg🇷🇺

    The general problem is studied on a simple example. A quantum particle in an infinite one-dimensional well potential is considered. Let the boundaries of well changes in a finite time $T$. The standard methods for calculating probability of transition from an initial to the final state are in general inapplicable since the states of different wells belong to different Hilbert spaces. If the final well covers only a part of the initial well (and, possibly, some outer part of the configuration space), the total probability of the transition from any stationary state of the initial well into {\bf all} possible states of the final well is less than 1 at $T\to 0$. If the problem is regularized with a finite-height potential well, this missing probability can be understood as a non-zero probability of transitions into the continuous spectrum, despite the fact that this spectrum disappears at the removal of regularization. This phenomenon ("transition to nowhere'') can result new phenomena in some fundamental problems, in particular at description of earlier Universe. We discuss also how to calculate the probabilities of discussed transitions at final $T$ for some ranges of parameters.

    ↳ quant-phhep-ph0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.