289 results on '"unitarity"'
Search Results
2. Building a boostless bootstrap for the bispectrum
- Author
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Enrico Pajer, Pajer, Enrico [0000-0002-7921-4479], and Apollo - University of Cambridge Repository
- Subjects
High Energy Physics - Theory ,Inflation (cosmology) ,Physics ,Unitarity ,010308 nuclear & particles physics ,Scalar (mathematics) ,Graviton ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Theoretical physics ,General Relativity and Quantum Cosmology ,High Energy Physics - Theory (hep-th) ,De Sitter universe ,0103 physical sciences ,cosmological perturbation theory ,Effective field theory ,Quantum gravity ,non-gaussianity ,primordial gravitational waves (theory) ,inflation ,Bispectrum - Abstract
The observation of primordial correlators by cosmological surveys is a very promising avenue to probe high energies and the perturbative regime of quantum gravity. Hence, it is imperative that we understand how these observables are shaped by the pillars of fundamental physics, namely unitarity, locality and symmetries. To this end, we study the three-point correlators of gravitons and scalar curvature perturbations around a quasi de Sitter spacetime. We identify a set of Bootstrap Rules that fully fix the form of these correlators in the asymptotic future, i.e. at the boundary, and make no reference to bulk time evolution. Importantly, our Boostless Bootstrap accounts for the ubiquitous (spontaneous) breaking of de Sitter boosts caused by any inflationary background. We show how all bispectra involving gravitons in single-clock, canonical inflation can be easily derived in this approach. We also derive for the first time the scalar bispectrum in the Effective Field Theory of inflation to any order in derivatives. In many cases, our derivation is computationally simpler than the corresponding explicit calculation, and makes particularly transparent the implications of locality, the choice of vacuum, and the underlying symmetries., 34+10 pages, 1 figure
- Published
- 2021
3. Conditional entanglement transfer via black holes: restoring predictability
- Author
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Ali Akil, Oscar C. O. Dahlsten, and Leonardo Modesto
- Subjects
Causality (physics) ,Black hole ,Physics ,General Relativity and Quantum Cosmology ,Unitarity ,General relativity ,Quantum mechanics ,Physics beyond the Standard Model ,General Physics and Astronomy ,Quantum entanglement ,Quantum information ,Quantum - Abstract
Hawking's black hole evaporation process suggests that we may need to choose between quantum unitarity and other basic physical principles such as no-signaling, entanglement monogamy, and the equivalence principle. We here show that the Hawking's quantum model for the black hole evaporation is consistent with the above fundamental principles. Our analysis does not involve exotic new physics, but rather uses standard quantum theory, general relativity, and the Einstein-Hilbert action including matter. We explicitly show that the whole state consisting of matter and radiation (in a joint superposition of different energy states) is pure at any stage of the evaporation process, including the particular case of $0$ mass. Moreover, after full evaporation the state for radiation at infinity is pure and in one-to-one correspondence with the initial state forming the black hole. Thus there is no information loss upon full evaporation according to the quantum information theory. The original entanglement of the black hole matter (if any) gets transferred to the outgoing particles via a process similar to entanglement swapping, without violation of causality (as proved explicitly). On the other hand, if the initial state is a tensor product state, the entanglement of Hawking particles, present in the intermediate phase, is broken when the black hole evaporates completely. Therefore, the final state (entangled or tensor product depending on the nature of initial state) after the full black hole evaporation is pure without loss of information.
- Published
- 2021
4. Pairs of operators with equal defect from unitarity and their relative index
- Author
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Vladimir Manuilov
- Subjects
Theoretical physics ,Relative index ,Algebra and Number Theory ,Unitarity ,Quantum mechanics ,010102 general mathematics ,0103 physical sciences ,010307 mathematical physics ,0101 mathematics ,01 natural sciences ,Mathematics - Published
- 2017
5. Shor–Movassagh chain leads to unusual integrable model
- Author
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Kun Hao, Bin Tong, Vladimir E. Korepin, and Olof Salberger
- Subjects
Statistics and Probability ,Physics ,Quantum Physics ,Reflection formula ,Nonlinear Sciences - Exactly Solvable and Integrable Systems ,Unitarity ,Integrable system ,FOS: Physical sciences ,General Physics and Astronomy ,Boundary (topology) ,Statistical and Nonlinear Physics ,Mathematical Physics (math-ph) ,Random walk ,Chain (algebraic topology) ,Modeling and Simulation ,Lax pair ,Exactly Solvable and Integrable Systems (nlin.SI) ,Quantum Physics (quant-ph) ,Ground state ,Mathematical Physics ,Mathematical physics - Abstract
The ground state of Shor-Movassagh chain can be analytically described by the Motzkin paths. There is no analytical description of the excited states, the model is not solvable. We prove the integrability of the model without interacting part in this paper [free Shor-Movassagh]. The Lax pair for the free Shor-Movassagh open chain is explicitly constructed. We further obtain the boundary $K$-matrices compatible with the integrability of the model on the open interval. Our construction provides a direct demonstration for the quantum integrability of the model, described by Yang-Baxter algebra. Due to the lack of crossing unitarity, the integrable open chain can not be constructed by the reflection equation (boundary Yang-Baxter equation)., Comment: 12 pages, 1 figure
- Published
- 2021
6. Cutting cosmological correlators
- Author
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Enrico Pajer, Sadra Jazayeri, Mang Hei Gordon Lee, Harry Goodhew, Apollo - University of Cambridge Repository, Apollo-University Of Cambridge Repository, Institut d'Astrophysique de Paris (IAP), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
High Energy Physics - Theory ,cosmological model ,optical theorem ,quantum cosmology ,spin ,01 natural sciences ,General Relativity and Quantum Cosmology ,de Sitter ,De Sitter universe ,Friedmann–Lemaître–Robertson–Walker metric ,Cosmological perturbation theory ,correlation function ,media_common ,Physics ,[PHYS.HTHE]Physics [physics]/High Energy Physics - Theory [hep-th] ,Propagator ,graviton ,symbols ,propagator ,resonance: oscillation ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,media_common.quotation_subject ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,space-time: Robertson-Walker ,quantum mechanics: wave function ,dispersion relation: linear ,Theoretical physics ,symbols.namesake ,Quantum cosmology ,0103 physical sciences ,conservation law ,unitarity ,tree approximation ,inflation ,010306 general physics ,perturbation theory ,Inflation (cosmology) ,010308 nuclear & particles physics ,paper ,monodromy ,inflation: slow-roll approximation ,Graviton ,Astronomy and Astrophysics ,boundary condition ,Universe ,High Energy Physics - Theory (hep-th) ,gravitation ,axion ,cosmological perturbation theory ,n-point function: 5 - Abstract
The initial conditions of our universe appear to us in the form of a classical probability distribution that we probe with cosmological observations. In the current leading paradigm, this probability distribution arises from a quantum mechanical wavefunction of the universe. Here we ask what the imprint of quantum mechanics is on the late time observables. We show that the requirement of unitary time evolution, colloquially the conservation of probabilities, fixes the analytic structure of the wavefunction and of all the cosmological correlators it encodes. In particular, we derive in perturbation theory an infinite set of single-cut rules that generalize the Cosmological Optical Theorem and relate a certain discontinuity of any tree-level $n$-point function to that of lower-point functions. Our rules are closely related to, but distinct from the recently derived Cosmological Cutting Rules. They follow from the choice of the Bunch-Davies vacuum and a simple property of the (bulk-to-bulk) propagator and are astoundingly general: we prove that they are valid for fields with a linear dispersion relation and any mass, any integer spin and arbitrary local interactions with any number of derivatives. They also apply to general FLRW spacetimes admitting a Bunch-Davies vacuum, including de Sitter, slow-roll inflation, power-law cosmologies and even resonant oscillations in axion monodromy. We verify the single-cut rules in a number of non-trivial examples, including four massless scalars exchanging a massive scalar, as relevant for cosmological collider physics, four gravitons exchanging a graviton, and a scalar five-point function., 36 + 18 pages, 4 figures
- Published
- 2021
7. Positivity bounds on dark energy: when matter matters
- Author
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Scott Melville, Johannes Noller, and Claudia de Rham
- Subjects
High Energy Physics - Theory ,Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Unitarity ,010308 nuclear & particles physics ,Gravitational wave ,FOS: Physical sciences ,Astronomy and Astrophysics ,General Relativity and Quantum Cosmology (gr-qc) ,Parameter space ,01 natural sciences ,General Relativity and Quantum Cosmology ,Causality (physics) ,Theoretical physics ,High Energy Physics - Theory (hep-th) ,UV completion ,0103 physical sciences ,Dark energy ,Effective field theory ,010303 astronomy & astrophysics ,Axiom ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Positivity bounds - constraints on any low-energy effective field theory imposed by the fundamental axioms of unitarity, causality and locality in the UV - have recently been used to constrain scalar-tensor theories of dark energy. However, the coupling to matter fields has so far played a limited role. We show that demanding positivity when including interactions with standard matter fields leads to further constraints on the dark energy parameter space. We demonstrate how implementing these bounds as theoretical priors affects cosmological parameter constraints and explicitly illustrate the impact on a specific Effective Field Theory for dark energy. We also show in this model that the existence of a standard UV completion requires that gravitational waves must travel superluminally on cosmological backgrounds., 14+6 pages, 2 figures; v2: minor clarifications added, matches published version
- Published
- 2021
8. Classical and quantum gravity with fractional operators
- Author
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Gianluca Calcagni and Agencia Estatal de Investigación (España)
- Subjects
High Energy Physics - Theory ,Physics ,Physics and Astronomy (miscellaneous) ,Unitarity ,General relativity ,Quantum gravity ,Graviton ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,General Relativity and Quantum Cosmology ,Alternative gravity theories ,Fractional calculus ,High Energy Physics::Theory ,Operator (computer programming) ,High Energy Physics - Theory (hep-th) ,Fractional operators ,Multi-fractional spacetimes ,Covariant transformation ,Scalar field ,Mathematical physics - Abstract
26 pags., 1 fig. -- This is a companion article to 2021 Class. Quantum Grav. 38 165006. -- This article is corrected by 2021 Class. Quantum Grav. 38 169601, Following the same steps made for a scalar field in a parallel publication, we propose a class of perturbative theories of quantum gravity based on fractional operators, where the kinetic operator of the graviton is made of either fractional derivatives or a covariant fractional d'Alembertian. The classical action for each theory is constructed and the equations of motion are derived. Unitarity and renormalizability of theories with a fractional d'Alembertian are also considered. We argue that unitarity and power-counting renormalizability never coexist, although in some cases one-loop unitary and finiteness are possible. One of the theories is unitary and infrared-finite and can serve as a ghost-free model with large-scale modifications of general relativity., The author is supported by the I+D Grants FIS2017-86497-C2-2-P and PID2020-118159GBC41 of the Spanish Ministry of Science and Innovation.
- Published
- 2021
9. Dark lump excitations in superuid Fermi gases.
- Author
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Xu Yan-Xia and Duan Wen-Shan
- Subjects
- *
ELECTRON gas , *NUCLEAR excitation , *LINEAR systems , *NONLINEAR systems , *SOLITONS , *THEORY of wave motion , *LIMIT theorems - Abstract
We study the linear and nonlinear properties of two-dimensional matter-wave pulses in disk-shaped superfluid Fermi gases. A Kadomtsev-Petviashvili I (KPI) solitary wave has been realized for superfluid Fermi gases in the limited cases of Bardeen-Cooper-Schrieffer (BCS) regime, Bose-Einstein condensate (BEC) regime, and unitarity regime. Onelump solution as well as one-line soliton solutions for the KPI equation are obtained, and two-line soliton solutions with the same amplitude are also studied in the limited cases. The dependence of the lump propagating velocity and the sound speed of two-dimensional superfluid Fermi gases on the interaction parameter are investigated for the limited cases of BEC and unitarity. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
10. Does Palatini Higgs inflation conserve unitarity?
- Author
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J. McDonald
- Subjects
High Energy Physics - Theory ,Physics ,Inflation (cosmology) ,Particle physics ,Unitarity ,High Energy Physics::Phenomenology ,Electroweak interaction ,FOS: Physical sciences ,Astronomy and Astrophysics ,Coupling (probability) ,Standard Model ,High Energy Physics - Phenomenology ,General Relativity and Quantum Cosmology ,High Energy Physics - Phenomenology (hep-ph) ,High Energy Physics - Theory (hep-th) ,Higgs boson ,Quantum gravity ,High Energy Physics::Experiment ,Scalar curvature - Abstract
In the conventional metric formulation of gravity, the Higgs Inflation model violates unitarity in the electroweak vacuum in Higgs scattering at the energy scale $\Lambda \sim M_{Pl}/\xi$, where $\xi \sim 10^4$ is the non-minimal coupling of the Higgs to the Ricci scalar. In the Palatini formulation it is commonly believed that $\Lambda \sim M_{Pl}/\sqrt{\xi}$, where $\xi \sim 10^{9}$. Here we reconsider unitarity violation in the electroweak vacuum in the Palatini formulation. We argue that there is no unitarity violation in Higgs scattering in the Palatini non-minimally coupled Standard Model in the electroweak vacuum at energies below the Planck scale. In this case Palatini Higgs Inflation completely conserves unitarity and is consistent at all energies up to those at which quantum gravity becomes important. If true, this would imply that Palatini Higgs Inflation has a significant advantage over metric Higgs Inflation., Comment: 8 pages. Additional reference. Published in JCAP
- Published
- 2021
11. The Cosmological Optical Theorem
- Author
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Harry Goodhew, Enrico Pajer, Sadra Jazayeri, Pajer, Enrico [0000-0002-7921-4479], and Apollo - University of Cambridge Repository
- Subjects
High Energy Physics - Theory ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,quantum cosmology ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,General Relativity and Quantum Cosmology ,De Sitter universe ,0103 physical sciences ,physics of the early universe ,inflation ,Quantum field theory ,Mathematical physics ,Inflation (cosmology) ,Physics ,Unitarity ,010308 nuclear & particles physics ,paper ,Scalar (physics) ,Graviton ,Astronomy and Astrophysics ,Optical theorem ,High Energy Physics - Theory (hep-th) ,particle physics - cosmology connection ,Trispectrum ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
The unitarity of time evolution, or colloquially the conservation of probability, sits at the heart of our descriptions of fundamental interactions via quantum field theory. The implications of unitarity for scattering amplitudes are well understood, for example through the optical theorem and cutting rules. In contrast, the implications for in-in correlators in curved spacetime and the associated wavefunction of the universe, which are measured by cosmological surveys, are much less transparent. For fields of any mass in de Sitter spacetime with general local interactions, which need not be invariant under de Sitter isometries, we show that unitarity implies an infinite set of relations among the coefficients $ \psi_{n} $ of the wavefunction of the universe with $ n $ fields, which we name Cosmological Optical Theorem. For contact diagrams, our result dictates the analytic structure of $ \psi_{n} $ and strongly constrains its form. For example, any correlator with an odd number of conformally-coupled scalar fields and any number of massless scalar fields must vanish. For four-point exchange diagrams, the Cosmological Optical Theorem yields a simple and powerful relation between $ \psi_{3} $ and $ \psi_{4} $, or equivalently between the bispectrum and trispectrum. As explicit checks of this relation, we discuss the trispectrum in single-field inflation from graviton exchange and self-interactions. Moreover, we provide a detailed derivation of the relation between the total-energy pole of cosmological correlators and flat-space amplitudes. We provide analogous formulae for sub-diagram singularities. Our results constitute a new, powerful tool to bootstrap cosmological correlators., Comment: 37+19 pages, 4 figures
- Published
- 2021
12. The Role of a 1 (1260) in π − p → a 1 − (1260) p and π − p → π − ρ 0 p Reactions Near Threshold
- Author
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Chen Cheng, Ju-Jun Xie, and Xu Cao
- Subjects
Physics ,Coupling constant ,Physics and Astronomy (miscellaneous) ,Meson ,Unitarity ,010308 nuclear & particles physics ,Form factor (quantum field theory) ,State (functional analysis) ,01 natural sciences ,Resonance (particle physics) ,Near threshold ,Cross section (physics) ,0103 physical sciences ,Atomic physics ,010306 general physics - Abstract
We report on a theoretical study of the π− p → a1 −(1260)p and π−p → π− ρ0p reactions near threshold within an effective Lagrangian approach. The production process is described by t-channel ρ0 meson exchange. For the π−p → π−ρ0p reaction, the final π−p0 results from the decay of the a1(1260) resonance, which is assumed as a dynamically generated state from the K* and ρπ coupled channel interactions. We calculate the total cross section of the π−p → a1 −(1260)p reaction. It is shown that, with the coupling constant of the a1(1260) to ρπ channel obtained from the chiral unitary theory and a cut off parameter Λρ ~ 1.5 GeV in the form factors, the experimental measurement can be reproduced. Furthermore, the total and differential cross sections of π−p → a1 −(1260)p → π−ρ0p reaction are evaluated, and it is expected that our model calculations can be tested by future experiments. These reactions are important for the study of the a1(1260) resonance and would provide further constraints on the properties of the a1(1260) state.
- Published
- 2016
13. Properly ordered dimers, R -charges, and an efficient inverse algorithm
- Author
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Daniel R. Gulotta
- Subjects
Physics ,High Energy Physics - Theory ,Nuclear and High Energy Physics ,Field (physics) ,Unitarity ,Diagram ,FOS: Physical sciences ,Gauge (firearms) ,Theoretical physics ,High Energy Physics::Theory ,Singularity ,Mathematics::Algebraic Geometry ,High Energy Physics - Theory (hep-th) ,Invariant (mathematics) ,Central charge ,Mathematics::Symplectic Geometry ,Stack (mathematics) - Abstract
The $\mathcal{N}=1$ superconformal field theories that arise in AdS-CFT from placing a stack of D3-branes at the singularity of a toric Calabi-Yau threefold can be described succinctly by dimer models. We present an efficient algorithm for constructing a dimer model from the geometry of the Calabi-Yau. Since not all dimers produce consistent field theories, we perform several consistency checks on the field theories produced by our algorithm: they have the correct number of gauge groups, their cubic anomalies agree with the Chern-Simons coefficients in the AdS dual, and all gauge invariant chiral operators satisfy the unitarity bound. We also give bounds on the ratio of the central charge of the theory to the area of the toric diagram. To prove these results, we introduce the concept of a properly ordered dimer., 33 pages, 19 figures, some corrections and clarifications
- Published
- 2019
14. A Proof of Factorization Theorem of Drell–Yan Process at Operator Level
- Author
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Gao-Liang Zhou
- Subjects
Physics ,Physics and Astronomy (miscellaneous) ,Unitarity ,010308 nuclear & particles physics ,High Energy Physics::Lattice ,Operator (physics) ,Nuclear Theory ,High Energy Physics::Phenomenology ,Drell–Yan process ,01 natural sciences ,Gluon ,symbols.namesake ,Factorization ,Quantum electrodynamics ,0103 physical sciences ,Weierstrass factorization theorem ,symbols ,High Energy Physics::Experiment ,Nuclear Experiment ,010306 general physics ,Glauber ,Mathematical physics ,Boson - Abstract
An alternative proof of factorization theorem for Drell–Yan process that works at operator level is presented in this paper. Contributions of interactions after the hard collision for such inclusive processes are proved to be canceled at operator level according to the unitarity of time evolution operator. After this cancellation, there are no longer leading pinch singular surface in Glauber region in the time evolution of electromagnetic currents. Effects of soft gluons are absorbed into Wilson lines of scalar-polarized gluons. Cancelation of soft gluons is attribute to unitarity of time evolution operator and such Wilson lines.
- Published
- 2016
15. The Ξ* and Ωη Interaction Within a Chiral Unitary Approach
- Author
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X. R. Chen, Si-Qi Xu, Ju-Jun Xie, and Duo-Jie Jia
- Subjects
Physics ,Physics and Astronomy (miscellaneous) ,Unitarity ,010308 nuclear & particles physics ,Nuclear Theory ,Strangeness ,01 natural sciences ,Unitary state ,Baryon ,Amplitude ,Isospin ,Quantum mechanics ,0103 physical sciences ,S-wave ,010306 general physics ,Spin-½ - Abstract
In this work we study the interaction of the coupled channels Ωη and within the chiral unitary approach. The systems under consideration have total isospins 0, strangeness S = −3, and spin 3/2. We study the s wave interaction which implies that the possible resonances generated in the system can have spin-parity JP = 3/2−. The unitary amplitudes in coupled channels develop poles that can be associated with some known baryonic resonances. We find there is a dynamically generated 3/2− Ω state with mass around 1800 MeV, which is in agreement with the predictions of the five-quark model.
- Published
- 2016
16. Combined Analysis of CP Properties of Higgs Boson in Effective Higgs Lagrangian
- Author
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Ying Zhang and Rong Li
- Subjects
Physics ,Particle physics ,Physics and Astronomy (miscellaneous) ,Unitarity ,010308 nuclear & particles physics ,High Energy Physics::Phenomenology ,Electroweak interaction ,01 natural sciences ,symbols.namesake ,0103 physical sciences ,Effective field theory ,Higgs boson ,symbols ,CP violation ,High Energy Physics::Experiment ,010306 general physics ,Lagrangian ,Free parameter ,Boson - Abstract
CP violation effects of the Higgs stem from not only the CP mixing state but also the CP-violation couplings to electroweak bosons. The two CPV sources are combinedly studied based on an effective Higgs Lagrangian. The constraints from unitarity limits for WW and ZZ scatterings are investigated. We classify free parameters into five cases to analyze CP properties of the Boson. The allowed ranges are shown from fitting results to the signal strengths of the Higgs measured by ATLAS and CMS.
- Published
- 2016
17. Finite W-superalgebras and quadratic spacetime supersymmetries
- Author
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Peter D. Jarvis, L. A. Yates, Eric Ragoucy, Laboratoire d'Annecy-le-Vieux de Physique Théorique (LAPTH), and Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)
- Subjects
dimension: 6 ,High Energy Physics - Theory ,Statistics and Probability ,Poisson bracket ,dimension: 4 ,triplet ,boson: symmetry ,supersymmetry: algebra ,[PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph] ,FOS: Physical sciences ,General Physics and Astronomy ,W-algebra ,algebra: conformal ,symmetry: algebra ,High Energy Physics::Theory ,Mathematics::Quantum Algebra ,Lie algebra ,unitarity ,Lie ,Mathematics::Representation Theory ,sparticle ,Mathematical Physics ,Mathematical physics ,Mathematics ,[PHYS.HTHE]Physics [physics]/High Energy Physics - Theory [hep-th] ,constraint: Hamiltonian ,High Energy Physics::Phenomenology ,Supercharge ,Statistical and Nonlinear Physics ,Mathematical Physics (math-ph) ,Supersymmetry ,supercharge ,Superalgebra ,High Energy Physics - Theory (hep-th) ,space-time ,multiplet ,Modeling and Simulation ,graded ,Superconformal algebra ,singleton ,Supersymmetry algebra - Abstract
We consider Lie superalgebras under constraints of Hamiltonian reduction, yielding finite $W$-superalgebras which provide candidates for quadratic spacetime superalgebras. These have an undeformed bosonic symmetry algebra (even generators) graded by a fermionic sector (supersymmetry generators) with anticommutator brackets which are quadratic in the even generators. We analyze the reduction of several Lie superalgebras of type $gl(M|N)$ or $osp(M|2N)$ at the classical (Poisson bracket) level, and also establish their quantum (Lie bracket) equivalents. Purely bosonic extensions are also considered. As a special case we recover a recently identified quadratic superconformal algebra, certain of whose unitary irreducible massless representations (in four dimensions) are "zero-step" multiplets, with no attendant superpartners. Other cases studied include a six dimensional quadratic superconformal algebra with vectorial odd generators, and a variant quadratic superalgebra with undeformed $osp(1|2N)$ singleton supersymmetry, and a triplet of spinorial supercharges., 14 pages, Latex
- Published
- 2020
18. Inflation in motion: unitarity constraints in effective field theories with (spontaneously) broken Lorentz symmetry
- Author
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Scott Melville and Tanguy Grall
- Subjects
Inflation (cosmology) ,Physics ,Theoretical physics ,Field (physics) ,Unitarity ,Motion (geometry) ,Astronomy and Astrophysics - Published
- 2020
19. KLEVER: An experiment to measure BR(KL→π0vv¯) at the CERN SPS
- Author
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M. Van Dijk
- Subjects
History ,Particle physics ,Large Hadron Collider ,Unitarity ,Series (mathematics) ,010308 nuclear & particles physics ,Computer science ,Physics beyond the Standard Model ,Measure (physics) ,01 natural sciences ,Computer Science Applications ,Education ,Beamline ,0103 physical sciences ,010306 general physics ,Particle flux - Abstract
The KLEVER experiment aims to measure BR ( K L → π 0 v v ¯ ) , supplementing the ongoing NA62 measurement of BR ( K + → π + v v ¯ ) , to provide new input on CKM unitarity and potentially new physics. KLEVER is undergoing continuous development, with particular efforts focused on the design of the target and the beamline. As described here, adaptations are required relative to the K12 beamline in its current format, and a series of simulations has been performed to ensure that an adequate particle flux can be achieved while simultaneously suppressing problematic backgrounds.
- Published
- 2020
20. An Inert Scalar In The S3 Symmetric Model
- Author
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E. A. Garcés, H. Reyes-González, Myriam Mondragon, Catalina Espinoza, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)
- Subjects
History ,satellite: Planck ,Scalar (mathematics) ,Dark matter ,Parameter space ,01 natural sciences ,Education ,doublet ,symbols.namesake ,Theoretical physics ,0103 physical sciences ,unitarity ,symmetry: SU(2) ,Planck ,010306 general physics ,Physics ,Unitarity ,010308 nuclear & particles physics ,dark matter: relic density ,High Energy Physics::Phenomenology ,Permutation group ,Computer Science Applications ,[PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph] ,Irreducible representation ,symbols ,Higgs boson - Abstract
We consider the S3 symmetric extension of the Standard Model in which all the irreducible representations of the permutation group are occupied by SU(2) scalar doublets, one of which is taken as inert. We study the parameter space of the model probing points against physical constraints ranging from unitarity tests to experimental Higgs searches limits. We find that the latter constraints severely restrict the parameter space of the model, and that the relic density of the dark matter candidates lies below the Planck bound for a large portion of the probed regions.
- Published
- 2020
21. Possible Odderon exchange in pp and elastic collisions at the TOTEM experiment *
- Author
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Juan Lu, Zhi-Jie Fang, and Li-Juan Zhou
- Subjects
Physics ,Elastic scattering ,Nuclear and High Energy Physics ,Particle physics ,Unitarity ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,01 natural sciences ,Elastic collision ,Scattering amplitude ,Regge theory ,Pomeron ,Amplitude ,0103 physical sciences ,010306 general physics ,Instrumentation ,Energy (signal processing) - Abstract
Based on the Froissart-Martin theorem, the Regge theory and the possible Odderon exchange, the total cross-section and the ratio of the real to imaginary parts of the forward scattering amplitude in the and elastic collisions in the TOTEM energy region are studied in the FPO model. We consider the contributions of the Froissart bound and of the Pomeron, Reggeon and Odderon exchange terms in the scattering amplitude of the and elastic collisions. Using the Odderon intercept , our theoretical predictions are in good agreement with the recent results of the TOTEM experiment. These results show that the Odderon, corresponding to the odd elastic scattering amplitude, is likely to exist.
- Published
- 2020
22. A divergent volume for black holes calls for no ‘firewall’
- Author
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Li You and Baocheng Zhang
- Subjects
High Energy Physics - Theory ,Physics ,Quantum Physics ,Physics and Astronomy (miscellaneous) ,Unitarity ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,Quantum entanglement ,01 natural sciences ,Noncommutative geometry ,General Relativity and Quantum Cosmology ,Black hole ,Theoretical physics ,Hawking ,High Energy Physics - Theory (hep-th) ,0103 physical sciences ,Radiation process ,Quantum Physics (quant-ph) ,010306 general physics ,Unitary evolution ,Black hole thermodynamics - Abstract
The presumption that Hawking radiations are thermally distributed can be considered to result from their entanglement with the internal degrees of freedom for a black hole. This leads to the "firewall" paradox if unitary evolution continues into Page's time when a black hole evaporates away half of its initial entropy. However, if the interior of a black hole houses sufficient degrees of freedom to maintain entanglement with the outside at all times, unitarity can be preserved during the complete radiation process and no firewall will be required. This paper proposes a scenario that rescinds firewall by introducing the concept of volume for a black hole. Based on the operational definition by Christodoulou and Rovelli [1], we show that the volume and its associated entropy for a collapsed black hole diverges if the final evaporation stage is treated using noncommutative space. This implicates the interior of a black hole possesses adequate space to store information for a black hole of any mass, like the inside of a "magician's bag".
- Published
- 2020
23. Unitary transformation of general nonoverlapping-image multimode interference couplers with any input and output ports*
- Author
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Weihua Han, Zezheng Li, and Zhiyong Li
- Subjects
Physics ,Unitarity ,C band ,Phase (waves) ,General Physics and Astronomy ,02 engineering and technology ,Unitary transformation ,Optical field ,021001 nanoscience & nanotechnology ,Topology ,01 natural sciences ,Matrix (mathematics) ,Transformation (function) ,Splitter ,0103 physical sciences ,010306 general physics ,0210 nano-technology - Abstract
An explanation of optical unitary transformation is presented for general nonoverlapping-image multimode interference (MMI) couplers with any number of input and output ports. The light transformation in the MMI coupler can be considered as an optical field matrix acting on an input light column vector. We investigate the general phase principle of output light image. The complete proof of nonoverlapping-image MMI coupler’s optical unitarity along with the phase analysis of matrix element is provided. Based on a two-dimensional finite-difference time-domain (2D-FDTD) simulation, the unitary transformation is obtained for a 4 × 4 nonoverlapping-image MMI coupler within a deviation of 4 × 10−2 for orthogonal invariance and 8 × 10−2 for transvection invariance in the C-band spectral range. A compact 1 × 4 splitter based on cascaded MMI coupler is proposed, showing a phase deviation less than 5.4° while maintaining a low-loss performance in C-band spectra.
- Published
- 2020
24. A Study on the Correlation Between Poles and Cuts in ππ Scattering*
- Author
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Ulf-G. Meißner, Tao Luo, Xian-Wei Kang, and Ling-Yun Dai
- Subjects
Physics ,Particle physics ,Chiral perturbation theory ,Physics and Astronomy (miscellaneous) ,Unitarity ,010308 nuclear & particles physics ,Scattering ,01 natural sciences ,High Energy Physics - Phenomenology ,Virtual state ,Amplitude ,0103 physical sciences ,Pi ,ddc:530 ,010306 general physics ,Mathematical physics - Abstract
In this paper we propose a dispersive method to describe two-body scattering with unitarity imposed. This approach is applied to elastic $\pi\pi$ scattering. The amplitudes keep single-channel unitarity and describe the experimental data well, and the low-energy amplitudes are consistent with that of chiral perturbation theory. The pole locations of the $\sigma$, $f_0(980)$, $\rho(770)$ and $f_2(1270)$ and their couplings to $\pi\pi$ are obtained. A virtual state appearing in the isospin-two S-wave is confirmed. The correlations between the left (and right) hand cut and the poles are discussed. Our results show that the poles are more sensitive to the right hand cut rather than the left hand cut. The proposed method could be used to study other two-body scattering processes., Comment: 10 pages, 4 figures
- Published
- 2019
25. Light neutrino masses from a non-Hermitian Yukawa theory
- Author
-
Carl M. Bender, Jean Alexandre, and Peter Millington
- Subjects
High Energy Physics - Theory ,History ,math-ph ,Dirac (software) ,FOS: Physical sciences ,Lorentz covariance ,01 natural sciences ,Education ,Theoretical physics ,math.MP ,High Energy Physics - Phenomenology (hep-ph) ,0103 physical sciences ,010306 general physics ,Conserved current ,Mathematical Physics ,Physics ,Unitarity ,010308 nuclear & particles physics ,hep-th ,High Energy Physics::Phenomenology ,Yukawa potential ,hep-ph ,Mathematical Physics (math-ph) ,Hermitian matrix ,Computer Science Applications ,Massless particle ,High Energy Physics - Phenomenology ,High Energy Physics - Theory (hep-th) ,Neutrino - Abstract
Working within the context of PT-symmetric quantum mechanics, we begin by describing a non-Hermitian extension of QED that is both Lorentz invariant and consistent with unitarity. We show that the non-Hermitian Dirac mass matrix of this theory exhibits an exceptional point, corresponding to an effectively massless theory whose conserved current is either right- or left-chiral dominated. With this inspiration, we are able to construct a non-Hermitian model of light Dirac neutrino masses from Hermitian and anti-Hermitian Yukawa couplings that are both of order unity. We finish by highlighting potential phenomenological implications of this model., Comment: 10 pages, 1 figure. Prepared for the proceedings of DISCRETE2016: the Fifth Symposium on Prospects in the Physics of Discrete Symmetries, 28 November-3 December 2016, University of Warsaw, Poland, to appear in the Journal of Physics: Conference Series (JPCS). Presented by P. Millington
- Published
- 2017
26. Reflective scattering and color conductivity in hadron collisions
- Author
-
N. E. Tyurin and S. M. Troshin
- Subjects
Physics ,Nuclear physics ,Nuclear and High Energy Physics ,Unitarity ,Scattering ,Hadron ,Conductivity - Published
- 2019
27. Novel theoretical constraints for color-octet scalar models *
- Author
-
Li Cheng, Otto Eberhardt, Christopher W. Murphy, Ministerio de Economía y Competitividad (España), and Ministerio de Ciencia, Innovación y Universidades (España)
- Subjects
Physics ,Nuclear and High Energy Physics ,Unitarity ,Octet ,010308 nuclear & particles physics ,Physics beyond the Standard Model ,High Energy Physics::Phenomenology ,Scalar (mathematics) ,Astronomy and Astrophysics ,Scalar potential ,Renormalization group ,01 natural sciences ,Theoretical physics ,0103 physical sciences ,Perturbation theory (quantum mechanics) ,Electroweak scale ,010306 general physics ,Instrumentation - Abstract
We study the theoretical constraints on a model whose scalar sector contains one color octet and one or two color singlet SU(2) L doublets. To ensure unitarity of the theory, we constrain the parameters of the scalar potential for the first time at the next-to-leading order in perturbation theory. Moreover, we derive new conditions guaranteeing the stability of the potential. We employ the HEPfit package to extract viable parameter regions at the electroweak scale and test the stability of the renormalization group evolution up to the multi-TeV region. Furthermore, we set upper limits on the scalar mass splittings. All results are given for both cases with and without a second scalar color singlet.
- Published
- 2019
28. Preliminary study for developing instantaneous quantum computing algorithms (IQCA)
- Author
-
Richard L Amoroso
- Subjects
Physics ,History ,Photon ,Speedup ,Unitarity ,Qubit ,Duality (mathematics) ,Unified field theory ,Algorithm ,Quantum ,Computer Science Applications ,Education ,Quantum computer - Abstract
Since the mid-1990s theoretical quadratic exponential and polynomial Quantum Computing (QC) speedup algorithms have been discussed. Recently the advent of relativistic information processing (RIP) introducing a relativistic qubit (r-qubit) with additional degrees of freedom beyond the current Hilbert space Bloch 2-sphere qubit formalism extended theory has appeared. In this work a penultimate form of QC speedup – Instantaneous Quantum Computing Algorithms (IQCA) is proposed. Discussion exists on passing beyond the quantum limits of locality and unitarity heretofore restricting the evolution of quantum systems to the standard Copenhagen Interpretation. In that respect as introduced in prior work an ontological-phase topological QC avails itself of extended modeling. As well-known by EPR experiments instantaneous connectivity exists inherently in the nonlocal arena. As our starting point we utilize Bohm’s super-implicate order where inside a wave packet a super-quantum potential introduces nonlocal connectivity. Additionally EPR experiments entangle simultaneously emitted photon pairs by parametric down-conversion. Operating an IQCA requires a parametric up-conversion cycle an M-Theoretic Unified Field Mechanical (MUFM) set of topological transformations beyond the current Galilean Lorentz-Poincairé transforms of the standard model (SM). Yang-Mills Kaluza-Klein (YM-KK) correspondence is shown to provide a path beyond the semi-quantum limit to realize the local-nonlocal duality required to implement IQCA.
- Published
- 2019
29. Tensor non-gaussianities from non-minimal coupling to the inflaton
- Author
-
Emanuela Dimastrogiovanni, Matteo Fasiello, Gianmassimo Tasinato, and David Wands
- Subjects
High Energy Physics - Theory ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Field (physics) ,gr-qc ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,General Relativity and Quantum Cosmology ,Theoretical physics ,High Energy Physics - Phenomenology (hep-ph) ,0103 physical sciences ,Tensor ,STFC ,Minimal coupling ,Physics ,Inflation (cosmology) ,Unitarity ,010308 nuclear & particles physics ,hep-th ,Scalar (physics) ,RCUK ,hep-ph ,Astronomy and Astrophysics ,Inflaton ,ST/P00055X/1 ,High Energy Physics - Phenomenology ,High Energy Physics - Theory (hep-th) ,astro-ph.CO ,ST/N000668/1 ,Bispectrum ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Tensor non-Gaussianity represents an important future probe of the physics of inflation. Inspired by recent works, we elaborate further on the possibility of significant primordial tensor non-Gaussianities sourced by extra fields during inflation. Unitarity constraints limit the impact of extra (spinning) particle content by means of a lower bound on the corresponding mass spectrum. For spin-2 particles, this takes the form of the well-known Higuchi bound. Massive ($m\gtrsim H$) particles will typically decay during inflation unless they are non-minimally coupled to the inflaton sector: the inflating field "lifts" the dynamics of the extra field(s), effectively getting around the limits imposed by unitarity. There exist several models that realize such a mechanism, but we focus here on the set-up of [1] where, through an EFT approach, one is able to capture the essential features common to an entire class of theories. In the presence of an extra massive spin-2 particle, the interactions in the tensor sector mimic very closely those in the scalar sector of quasi-single-field inflationary models. We calculate the tensor bispectrum in different configurations and extract its dependence on the extra tensor sound speed. We show in detail how one may obtain significant tensor non-Gaussianities whose shape-function interpolates between local and equilateral, depending on the mass of the extra field. We also estimate the LISA response functions to a tensor bispectrum supporting the intermediate-type shapes we find., 21 pages, 7 figures, References added
- Published
- 2019
30. Dimensional crossover in non-relativistic effective field theory
- Author
-
Silas R. Beane and Murtaza Jafry
- Subjects
Physics ,Quantum Physics ,Compactification (physics) ,Unitarity ,Atomic Physics (physics.atom-ph) ,FOS: Physical sciences ,Inverse ,Few-body systems ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Physics - Atomic Physics ,010305 fluids & plasmas ,Dimensional regularization ,Quantum Gases (cond-mat.quant-gas) ,0103 physical sciences ,Bound state ,Effective field theory ,Periodic boundary conditions ,Condensed Matter - Quantum Gases ,Quantum Physics (quant-ph) ,010306 general physics ,Mathematical physics - Abstract
Isotropic scattering in various spatial dimensions is considered for arbitrary finite-range potentials using non-relativistic effective field theory. With periodic boundary conditions, compactifications from a box to a plane and to a wire, and from a plane to a wire, are considered by matching S-matrix elements. The problem is greatly simplified by regulating the ultraviolet divergences using dimensional regularization with minimal subtraction. General relations among (all) effective-range parameters in the various dimensions are derived, and the dependence of bound states on changing dimensionality are considered. Generally, it is found that compactification binds the two-body system, even if the uncompactified system is unbound. For instance, compactification from a box to a plane gives rise to a bound state with binding momentum given by $\ln \left({\scriptstyle \frac{1}{2}}\left(3+\sqrt{5} \right) \right)$ in units of the inverse compactification length. This binding momentum is universal in the sense that it does not depend on the two-body interaction in the box. When the two-body system in the box is at unitarity, the S-matrices of the compactified two-body system on the plane and on the wire are given exactly as universal functions of the compactification length, Comment: 16 pages, 4 figures
- Published
- 2019
31. Unitarity constraints on non-minimal universal extra dimensional model
- Author
-
Tapoja Jha
- Subjects
Physics ,Nuclear and High Energy Physics ,Compactification (physics) ,Unitarity ,010308 nuclear & particles physics ,High Energy Physics::Phenomenology ,Scalar (mathematics) ,Kaluza–Klein theory ,FOS: Physical sciences ,01 natural sciences ,Upper and lower bounds ,Many-body problem ,Universal extra dimension ,Scattering amplitude ,High Energy Physics - Phenomenology ,High Energy Physics - Phenomenology (hep-ph) ,0103 physical sciences ,010306 general physics ,Mathematical physics - Abstract
We examine the unitarity constraints in gauge and scalar sectors of non-minimal Universal Extra Dimensional model. We show that some of the tree-level two-body scattering amplitudes in gauge and scalar sectors do not respect partial wave unitarity. Unitarity analysis of this model leads to an upper bound on corresponding boundary-localized (BLT) parameter which depends on the maximum number of Kaluza-Klein (KK) mode considered in the analysis. This upper bound of the relevant BLT parameter decreases with the increasing KK-modes. The results are, in effect, independent of the inverse of compactifiaction radius. The upper bound on BLT parameter also results in a lower bound on gauge and scalar KK-masses., 40 pages, 11 figures and 3 tables; added new discussions and figures; typos fixed; references added; matches published version
- Published
- 2018
32. Heavy mesons in a hadronic medium
- Author
-
Juan M. Torres-Rincon, Laura Tolos, Olena Romanets, Daniel Cabrera, and Luciano M. Abreu
- Subjects
History ,Particle physics ,Field (physics) ,Meson ,Nuclear Theory ,High Energy Physics::Lattice ,Hadron ,FOS: Physical sciences ,01 natural sciences ,Education ,Nuclear Theory (nucl-th) ,High Energy Physics - Phenomenology (hep-ph) ,0103 physical sciences ,Effective field theory ,B meson ,010306 general physics ,Nuclear Experiment ,Physics ,Unitarity ,010308 nuclear & particles physics ,High Energy Physics::Phenomenology ,Boltzmann equation ,Computer Science Applications ,Baryon ,High Energy Physics - Phenomenology ,High Energy Physics::Experiment - Abstract
We review the recent results of heavy meson diffusion in thermal hadronic matter. The interactions of D and B-bar mesons with other hadrons (light mesons and baryons) are extracted from effective field theories based on chiral and heavy-quark symmetries. When these guiding principles are combined with exact unitarity, physical values of the cross sections are obtained. These cross sections (which contain resonant contributions) are used to calculate the drag and diffusion coefficients of heavy mesons immersed in a thermal and dense medium. The transport coefficients are computed using a Fokker-Planck reduction of the Boltzmann equation., 4 pages, 3 figures. Contribution to the proceedings of the 15th International Conference on Strangeness in Quark Matter (SQM 2015), 06-11 Jul 2015. Dubna, Moscow region, Russia
- Published
- 2016
33. Pole Analysis on Unitarized SU(3) × SU(3) One Loop χPT Amplitudes
- Author
-
Han-qing Zheng, Xuan-Gong Wang, and Ling-Yun Dai
- Subjects
Physics ,Loop (topology) ,Matrix (mathematics) ,Chiral perturbation theory ,Amplitude ,Trace (linear algebra) ,Physics and Astronomy (miscellaneous) ,Unitarity ,Resonance ,Complex plane ,Mathematical physics - Abstract
We analyze ππ-K and πη-K couple channel [1,1] matrix Pade amplitudes of SU(3) × SU(3) chiral perturbation theory. By fitting phase shift and inelasticity data, we determine pole positions in different channels (f0(980), a0(980), f0(600), K*0(800), K*(892), ρ(770)) and trace their Nc trajectories. We stress that a couple channel Breit—Wigner resonance should exhibit two poles on different Riemann sheets and meet each other on the real axis when Nc = ∞. Poles are hence classified using this criteria and we conclude that K* (892) and ρ(770) are unambiguous Breit—Wigner resonances. For scalars the situation is much less clear. We find that f0(980) is a molecular state rather than a Breit—Wigner resonance, while a0(980), though behave oddly when varying Nc, do maintain a twin pole structure.
- Published
- 2012
34. Implications of the Daya Bay observation of θ 13 on the leptonic flavor mixing structure and CP violation
- Author
-
Zhi-zhong Xing
- Subjects
Physics ,Nuclear and High Energy Physics ,Particle physics ,Unitarity ,Daya bay ,High Energy Physics::Phenomenology ,Sigma ,Perturbation (astronomy) ,Astronomy and Astrophysics ,High Energy Physics - Experiment ,High Energy Physics - Phenomenology ,CP violation ,High Energy Physics::Experiment ,Neutrino ,Astrophysics - High Energy Astrophysical Phenomena ,Instrumentation ,Flavor ,Lepton - Abstract
The Daya Bay Collaboration has recently reported its first \bar{\nu}_e \to \bar{\nu}_e oscillation result which points to \theta_{13} \simeq 8.8^\circ \pm 0.8^\circ (best-fit \pm 1\sigma range) or \theta_{13} \neq 0^\circ at the 5.2\sigma level. The fact that this smallest neutrino mixing angle is not strongly suppressed motivates us to look into the underlying structure of lepton flavor mixing and CP violation. Two phenomenological strategies are outlined: (1) the lepton flavor mixing matrix U consists of a constant leading term U_0 and a small perturbation term \Delta U; and (2) the mixing angles of U are associated with the lepton mass ratios. Some typical patterns of U_0 are reexamined by constraining their respective perturbations with current experimental data. We illustrate a few possible ways to minimally correct U_0 in order to fit the observed values of three mixing angles. We point out that the structure of U may exhibit an approximate \mu-\tau permutation symmetry in modulus, and reiterate the geometrical description of CP violation in terms of the leptonic unitarity triangles. The salient features of nine distinct parametrizations of U are summarized, and its Wolfenstein-like expansion is presented by taking U_0 to be the democratic mixing pattern., Comment: RevTeX 25 pages, 1 figure, minor changes, version for publication
- Published
- 2012
35. Investigation of the rescattering effect in D decay
- Author
-
Qi-Chao Wang, Qing Gao, and Zhi-Yong Zhou
- Subjects
Nuclear physics ,Physics ,Nuclear and High Energy Physics ,Particle physics ,Unitarity ,Scattering ,High Energy Physics::Experiment ,Astronomy and Astrophysics ,Instrumentation - Abstract
With two-body unitarity equations, we demonstrate the relation between the data of Dalitz analysis of a D+ → K−π+π+ decay experiment and that of Kπ scattering, and point out that there might be some underestimated ambiguity in the existing data sets, if the I = 1/2 component of the Kπ system is dominant in this decay process. It is suggested that the unitarity constraints should be built in to deal with the raw data to obtain an improved result from the Dalitz analysis.
- Published
- 2011
36. Colorphilic spin-2 resonances in the LHC dijet channel
- Author
-
Elizabeth H. Simmons, Dennis Foren, and R. Sekhar Chivukula
- Subjects
Quark ,General Physics ,Particle physics ,Physics beyond the Standard Model ,collider phenomenology ,dijet channel ,FOS: Physical sciences ,spin-2 resonance ,01 natural sciences ,Mathematical Sciences ,High Energy Physics - Experiment ,High Energy Physics - Experiment (hep-ex) ,High Energy Physics - Phenomenology (hep-ph) ,0103 physical sciences ,Invariant mass ,010306 general physics ,Mathematical Physics ,Boson ,Physics ,colorphilic graviton ,Large Hadron Collider ,Unitarity ,hep-ex ,010308 nuclear & particles physics ,High Energy Physics::Phenomenology ,hep-ph ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,simplified model ,3. Good health ,Gluon ,Diquark ,High Energy Physics - Phenomenology ,Physical Sciences ,High Energy Physics::Experiment ,LHC - Abstract
Experiments at the LHC may yet discover a dijet resonance indicative of Beyond the Standard Model (BSM) physics. In this case, the question becomes: what BSM theories are consistent with the unexpected resonance? One possibility would be a spin-2 object called the colorphilic graviton--a spin-2 color-singlet particle which couples exclusively to the quark and gluon stress-energy tensors. We assess the possibility of this state's discovery in the dijet channel as an s-channel resonance, and report the regions of parameter space where colorphilic gravitons have not yet been excluded by LHC-13 data but still may be discovered in the dijet channel at LHC-14 for integrated luminosities of 0.3, 1, and 3 ab$^{-1}$. We then delineate which of those regions remain accessible to future collider searches, once one accounts for applicability of the narrow-width approximation, detector mass resolution, and self-consistency according to tree-level partial-wave unitarity. We discover that--despite the strong constraints unitarity imposes on collider searches--the colorphilic graviton remains potentially discoverable in the LHC dijet channel. A means of investigation would be to apply the color discriminant variable (CDV), a dimensionless combination of quantities (cross-section, decay width, and invariant mass) that can be quickly measured after the discovery of a dijet resonance. Previous publications have demonstrated the CDV's utility when applied to theories containing Z', colorons, excited quarks, and diquarks. We extend this analysis to the colorphilic graviton by applying the CDV to the appropriate region of parameter space. We conclude that resolvable, discoverable dijet resonances consistent with colorphilic gravitons span a narrower range of masses than those consistent with leptophobic Z' models, and can be distinguished from those originating from coloron, excited quark, and diquark models., Comment: 23 pages, 4 figures, updated notation and figures
- Published
- 2018
37. Two-pole structure of the ${D}_{0}^{* }(2400)$
- Author
-
Juan Nieves, Miguel Albaladejo, Feng-Kun Guo, and P. Fernandez-Soler
- Subjects
Physics ,History ,Unitarity ,Quantum mechanics ,Lattice field theory ,Mass spectrum ,Strong coupling ,Structure (category theory) ,Computer Science Applications ,Education - Published
- 2018
38. Calculation of Decay μ → e γ in R ξ Gauge in a Model of Electroweak-Scale Right-Handed Neutrinos
- Author
-
Bu Jian-Ping
- Subjects
Physics ,Particle physics ,Muon ,Physics and Astronomy (miscellaneous) ,Unitarity ,High Energy Physics::Phenomenology ,Unitarity gauge ,Massless particle ,Particle decay ,Quantum electrodynamics ,High Energy Physics::Experiment ,Electroweak scale ,Neutrino ,Lepton - Abstract
The lepton flavor violating process μ → eγ has been previously studied in a model of electroweak-scale right-handed neutrinos. In that work the decay amplitude was computed in unitarity gauge, augmented by some technical considerations that correct the leading term thus obtained. This complication arises because the mixing matrices appearing in the weak charged currents are not unitary in the model. In this paper, we recalculate the amplitude in Rξ gauge. The cancellation of the ξ dependence in the final result serves as a useful check to both the obtained amplitude and the technical points made in the previous work.
- Published
- 2010
39. Specific heat and effects of strong pairing fluctuations in a superfluid Fermi atom gas in the BCS-BEC crossover region
- Author
-
Daisuke Inotani, Pieter van Wyk, and Yoji Ohashi
- Subjects
Condensed Matter::Quantum Gases ,Physics ,History ,Condensed matter physics ,Unitarity ,Condensed Matter::Other ,Crossover ,Computer Science Applications ,Education ,Superfluidity ,Volume (thermodynamics) ,Pairing ,Atom ,Fermi gas ,Fermi Gamma-ray Space Telescope - Abstract
We theoretically investigate the specific heat at constant volume C V in the BCS(Bardeen-Cooper-Schrieffer)-BEC(Bose-Einstein-condensation)-crossover regime of an ultracold Fermi gas, below the superfluid phase transition temperature T c. Within the strong-coupling framework developed by Nozieres and Schmitt-Rink, we show that the temperature dependence of C V drastically changes as one passes through the crossover region, and is sensitive to strong fluctuations in the Cooper channel near the unitarity limit. We also compare our results to a recent experiment on a 6Li unitary Fermi gas. Since fluctuation effects are a crucial key in the BCS-BEC-crossover phenomenon, our results would be helpful in considering how the fermionic BCS superfluid changes into BEC with increasing the interaction strength, from the viewpoint of specific heat.
- Published
- 2018
40. Explaining dark matter and neutrino mass in the light of TYPE-II seesaw model
- Author
-
Anirban Biswas and Avirup Shaw
- Subjects
Physics ,Particle physics ,Large Hadron Collider ,Unitarity ,010308 nuclear & particles physics ,High Energy Physics::Phenomenology ,Dark matter ,FOS: Physical sciences ,Astronomy and Astrophysics ,01 natural sciences ,High Energy Physics - Phenomenology ,MAJORANA ,High Energy Physics - Phenomenology (hep-ph) ,Seesaw mechanism ,Seesaw molecular geometry ,0103 physical sciences ,High Energy Physics::Experiment ,Neutrino ,010306 general physics ,Vacuum expectation value - Abstract
With the motivation of simultaneously explaining dark matter and neutrino masses, mixing angles, we have invoked the Type-II seesaw model extended by an extra $SU(2)$ doublet $\Phi$. Moreover, we have imposed a $\mathbb{Z}_2$ parity on $\Phi$ which remains unbroken as the vacuum expectation value of $\Phi$ is zero. Consequently, the lightest neutral component of $\Phi$ becomes naturally stable and can be a viable dark matter candidate. On the other hand, light Majorana masses for neutrinos have been generated following usual Type-II seesaw mechanism. Further in this framework, for the first time, we have derived the full set of vacuum stability and unitarity conditions, which must be satisfied to obtain a stable vacuum as well as to preserve the unitarity of the model respectively. Thereafter, we have performed extensive phenomenological studies of both dark matter and neutrino sectors considering all possible theoretical and current experimental constraints. Finally, we have also discussed a qualitative collider signatures of dark matter and associated odd particles at the 13 TeV Large Hadron Collider., Comment: 49 pages, 11 figures, 8 Tables, some typos corrected
- Published
- 2018
41. Constraining Elko dark matter at the LHC with monophoton events
- Author
-
J. M. Hoff da Silva, Laura Duarte, M. Dias, F. de Campos, Alexandre Alves, Universidade Federal de São Paulo (UNIFESP), and Universidade Estadual Paulista (Unesp)
- Subjects
Physics ,Particle physics ,Photon ,Large Hadron Collider ,Unitarity ,010308 nuclear & particles physics ,Physics beyond the Standard Model ,High Energy Physics::Phenomenology ,Dark matter ,FOS: Physical sciences ,General Physics and Astronomy ,Fermion ,01 natural sciences ,High Energy Physics - Phenomenology ,High Energy Physics - Phenomenology (hep-ph) ,0103 physical sciences ,010306 general physics - Abstract
A mass dimension one fermion, also known as Elko, constitutes a dark matter candidate which might interact with photons at the tree level in a specific fashion. In this work, we investigate the constraints imposed by unitarity and LHC data on this type of interactions using the search for new physics in monophoton events. We found that Elkos which can explain the dark matter relic abundance mainly through electromagnetic interactions are excluded at the 95\%CL by the 8 TeV LHC data for masses up to 1 TeV., Comment: 6 pages, 4 figures
- Published
- 2018
42. The Born–Oppenheimer method, quantum gravity and matter
- Author
-
Giovanni Venturi, Alessandro Tronconi, Alexander Yu. Kamenshchik, Kamenchtchik, A., Tronconi, A., and Venturi, G.
- Subjects
High Energy Physics - Theory ,Physics and Astronomy (miscellaneous) ,quantum cosmology ,Born–Oppenheimer approximation ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,01 natural sciences ,General Relativity and Quantum Cosmology ,Classical limit ,Gravitation ,Theoretical physics ,symbols.namesake ,0103 physical sciences ,010306 general physics ,Born-Oppenheimer approximation ,Quantum ,Physics ,Unitarity ,Wheeler-De Witt equation ,010308 nuclear & particles physics ,wave function of the universe ,High Energy Physics - Theory (hep-th) ,Loop space ,symbols ,Quantum gravity ,Scalar field - Abstract
We illustrate and examine diverse approaches to the quantum matter-gravity system which refer to the Born-Oppenheimer (BO) method. In particular we first examine a quantum geometrodynamical approach introduced by other authors in a manner analogous to that previously employed by us, so as to include back reaction and non-adiabatic contributions. On including such effects it is seen that the unitarity violating effects previously found disappear. A quantum loop space formulation (based on a hybrid quantisation, polymer for gravitation and canonical for matter) also refers to the BO method. It does not involve the classical limit for gravitation and has a highly peaked initial scalar field state. We point out that it does not resemble in any way to our traditional BO approach. Instead it does resemble an alternative, canonically quantised, non BO approach which we have also previously discussed., 14 pages, no figures
- Published
- 2017
43. The Scattering of Massive Holes by Supercritical Impurity
- Author
-
Alexander Fedotov, Yu. E. Lozovik, V. M. Kuleshov, and V. D. Mur
- Subjects
Physics ,History ,Angular momentum ,Unitarity ,Condensed matter physics ,Scattering ,Graphene ,Quantum number ,Supercritical fluid ,Computer Science Applications ,Education ,law.invention ,Pair production ,law ,Charge carrier - Published
- 2017
44. Unitarity and stability conditions in a 4-Higgs doublet model with anS3-family symmetry
- Author
-
E. A. Garcés, M. Mondragón, Catalina Espinoza, and H. Reyes-González
- Subjects
Physics ,History ,Particle physics ,Unitarity ,010308 nuclear & particles physics ,01 natural sciences ,Stability (probability) ,Symmetry (physics) ,Computer Science Applications ,Education ,Stability conditions ,Theoretical physics ,0103 physical sciences ,Higgs boson ,010306 general physics - Published
- 2017
45. An improved variational method
- Subjects
Physics ,Nuclear and High Energy Physics ,Variational method ,Unitarity ,Scattering ,Quantum electrodynamics ,Applied mathematics ,Order (ring theory) ,Astronomy and Astrophysics ,Boundary value problem ,Wave function ,Instrumentation ,Communication channel - Abstract
In order to improve the unitarity of the S-matrix, an improved variational formulism is derived by proposing new generating functionals and adopting proper asymptotic boundary conditions for trial relative wave functions. The formulas with the weighted line-column balance for the single-channel and multi-channel scatterings, where the non-central interaction is implicitly considered, are presented. A numerical check is performed with a soluble model in a four coupled channel scattering problem. The result shows that the high accuracy and the unitarity of the S-matrix are reached.
- Published
- 2009
46. Analytic expression for the proton structure function in deep inelastic scattering
- Author
-
Wan Ren-Zhuo, Yuan Xian-Bao, Zhou Dai-Cui, and Xiang Wen-Chang
- Subjects
Physics ,Nuclear and High Energy Physics ,Particle physics ,Proton ,Unitarity ,Astronomy and Astrophysics ,HERA ,Inelastic scattering ,Deep inelastic scattering ,Color-glass condensate ,Dipole ,Quantum electrodynamics ,High Energy Physics::Experiment ,Instrumentation ,Glauber - Abstract
The analytic expression of proton in deep inelastic scattering is studied by using the color glass condensate model and the dipole picture. We get a better description of the HERA DIS data than the GBW model which was inspired by the Glauber model. We find that our model satisfies the unitarity limit and Froissart Bound which refers to an energy dependence of the total cross-section rising no more rapidly than In2 s.
- Published
- 2009
47. Quantum electrodynamics with arbitrary charge on a noncommutative space
- Author
-
Zhou Wan-Ping, Long Zheng-Wen, and Cai Shao-Hong
- Subjects
Physics ,Nuclear and High Energy Physics ,Unitarity ,Mathematics::Operator Algebras ,Astronomy and Astrophysics ,Charge (physics) ,Space (mathematics) ,Noncommutative geometry ,Quantum differential calculus ,Mathematics::K-Theory and Homology ,Mathematics::Quantum Algebra ,Quantum mechanics ,Quantum electrodynamics ,Noncommutative algebraic geometry ,Gauge theory ,Noncommutative quantum field theory ,Instrumentation - Abstract
Using the Seiberg-Witten map, we obtain a quantum electrodynamics on a noncommutative space, which has arbitrary charge and keep the gauge invariance to at the leading order in theta. The one-loop divergence and Compton scattering are reinvestigated. The noncommutative effects are larger than those in ordinary noncommutative quantum electrodynamics.
- Published
- 2009
48. Reggeon, Pomeron and Glueball, Odderon-Hadron-Hadron Interaction at High Energies — From Regge Theory to Quantum Chromodynamics
- Author
-
HU Zhao-Hui, Zhou Li-Juan, and MA Wei-Xing
- Subjects
Physics ,Quantum chromodynamics ,Regge theory ,Pomeron ,Particle physics ,Physics and Astronomy (miscellaneous) ,Unitarity ,Glueball ,High Energy Physics::Phenomenology ,Strong interaction ,Crossing ,High Energy Physics::Experiment ,Gluon - Abstract
Based on analysis of scattering matrix S, and its properties such as analyticity, unitarity Lorentz invariance, and crossing symmetry relation, the Regge theory was proposed to describe hadron-hadron scattering at high energies before the advent of QCD, and correspondingly a Reggeon concept was born as a mediator of strongly interaction. This theory serves as a successful approach and has explained a great number of experimental data successfully, which proves that the Regge theory can be regarded as a basic theory of hadron interaction at high energies and its validity in many applications. However, as new experimental data come out, we have some difficulties in explaining the data. The new experimental total cross section violates the predictions of Regge theory, which shows that Regge formalism is limited in its applications to high energy data. To understand new experimental measurements, a new exchange theory was consequently born and its mediator is called Pomeron, which has vacuum quantum numbers. The new theory named as Pomeron exchange theory which reproduces the new experimental data of diffractive processes successfully. There are two exchange mediators: Reggeon and Pomeron. Reggeon exchange theory can only produce data at the relatively lower energy region, while Pomeron exchange theory fits the data only at higher-energy region, separately. In order to explain the data in the whole energy region, we propose a Reggeon–Pomeron model to describe high-energy hadron-hadron scattering and other diffractive processes. Although the Reggeon–Pomeron model is successful in describing high-energy hadron-hadron interaction in the whole energy region, it is a phenomenological model. After the advent of QCD, people try to reveal the mystery of the phenomenological theory from QCD since hadron-hadron processes is a strong interaction, which is believed to be described by QCD. According to this point of view, we study the QCD nature of Reggeon and Pomeron. We claim that the Reggeon exchange is an exchange of multigluon, the color singlet gluon bound state. In particular, the Pomeron could be a Reggeized tensor glueball ξ(2230) with mass of 2.23 GeV, quantum numbers IG, JPC = 0+, 2++ and decay width of about 100 MeV. The glueball exchange theory reproduces data quite well. Accordingly, we believe that the Odderon, consisting of three Reggeized gluons, and predicted by QCD, should also contribute to hadron-hadron scattering and many other diffractive processes. We search for the Odderon by studying p and pp elastic scatterings at high energies. Our investigations on the differential cross section dσ/dt of hadron-hadron scattering at various energies and comparisons with experimental data show that the Odderon plays an essential role in fitting to data. Therefore, we suggest that the measurements should be urgently done in order to confirm the existences of the Odderon and to test QCD.
- Published
- 2008
49. On Factorization of Coupled Channel Scattering S Matrices
- Author
-
Fang Ke-Jie
- Subjects
Physics ,Physics and Astronomy (miscellaneous) ,Factorization ,Unitarity ,Scattering ,Simple (abstract algebra) ,Product (mathematics) ,Communication channel ,Mathematical physics ,S-matrix - Abstract
We investigate the problem on how to factorize a coupled channel scattering S matrix into a product of simple S matrices. Simple S matrix solutions are found, respecting unitarity, analyticity and being real analytic. The phase shift and its physical meaning produced by these simple S matrices are discussed.
- Published
- 2007
50. On the unitarity of higher derivative and nonlocal theories
- Author
-
Piotr Kosinski and Katarzyna Bolonek
- Subjects
High Energy Physics - Theory ,Statistics and Probability ,Physics ,Quantum Physics ,Unitarity ,FOS: Physical sciences ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Unitary state ,Theoretical physics ,High Energy Physics - Theory (hep-th) ,Simple (abstract algebra) ,Modeling and Simulation ,Quantum Physics (quant-ph) ,Computer Science::Databases ,Mathematical Physics - Abstract
We consider two simple models of higher-derivative and nonlocal quantu systems.It is shown that, contrary to some claims found in literature, they can be made unitary., 8 pages, no figures
- Published
- 2007
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