[ { "id": "authors:dhrht-k3q46", "collection": "authors", "collection_id": "dhrht-k3q46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230317-162727094", "type": "monograph", "title": "Stringy Dynamics from an Amplitudes Bootstrap", "author": [ { "family_name": "Cheung", "given_name": "Clifford", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Remmen", "given_name": "Grant N.", "orcid": "0000-0001-6569-8866", "clpid": "Remmen-Grant-N" } ], "abstract": "We describe an analytic procedure whereby scattering amplitudes are bootstrapped directly from an input mass spectrum and a handful of physical constraints: crossing symmetry, boundedness at high energies, and finiteness of exchanged spins. For an integer spectrum, this procedure gives a first principles derivation of a new infinite parameter generalization of the Veneziano amplitude that is unitary while exhibiting dual resonance and consistent high-energy behavior. Lifting to a q-deformed integer spectrum, we derive the Coon amplitude and its analogous generalizations. Finally, we apply this logic to derive an infinite class of deformed Virasoro-Shapiro amplitudes.", "publisher": "arXiv", "publication_date": "2023-02-23" }, { "id": "authors:19ej0-g6003", "collection": "authors", "collection_id": "19ej0-g6003", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220707-170611265", "type": "monograph", "title": "Geometry-Kinematics Duality", "author": [ { "family_name": "Cheung", "given_name": "Clifford", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Helset", "given_name": "Andreas", "orcid": "0000-0002-5904-3748", "clpid": "Helset-Andreas" }, { "family_name": "Parra-Martinez", "given_name": "Julio", "orcid": "0000-0003-0178-1569", "clpid": "Parra-Martinez-Julio" } ], "abstract": "We propose a mapping between geometry and kinematics that implies the classical equivalence of any theory of massless bosons -- including spin and exhibiting arbitrary derivative or potential interactions -- to a nonlinear sigma model (NLSM) with a momentum-dependent metric in field space. From this kinematic metric we construct a corresponding kinematic connection, covariant derivative, and curvature, all of which transform appropriately under general field redefinitions, even including derivatives. We show explicitly how all tree-level on-shell scattering amplitudes of massless bosons are equal to those of the NLSM via the replacement of geometry with kinematics. Lastly, we describe how the recently introduced geometric soft theorem of the NLSM, which universally encodes all leading and subleading soft scalar theorems, also captures the soft photon theorems.", "publisher": "arXiv", "publication_date": "2022-02-14" }, { "id": "authors:enwkb-z2d50", "collection": "authors", "collection_id": "enwkb-z2d50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201111-131014384", "type": "monograph", "title": "Scattering Amplitudes and the Navier-Stokes Equation", "author": [ { "family_name": "Cheung", "given_name": "Clifford", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Mangan", "given_name": "James", "clpid": "Mangan-James" } ], "abstract": "We explore the scattering amplitudes of fluid quanta described by the Navier-Stokes equation and its non-Abelian generalization. These amplitudes exhibit universal infrared structures analogous to the Weinberg soft theorem and the Adler zero. Furthermore, they satisfy on-shell recursion relations which together with the three-point scattering amplitude furnish a pure S-matrix formulation of incompressible fluid mechanics. Remarkably, the amplitudes of the non-Abelian Navier-Stokes equation also exhibit color-kinematics duality as an off-shell symmetry, for which the associated kinematic algebra is literally the algebra of spatial diffeomorphisms. Applying the double copy prescription, we then arrive at a new theory of a tensor bi-fluid. Finally, we present monopole solutions of the non-Abelian and tensor Navier-Stokes equations and observe a classical double copy structure.", "doi": "10.48550/arXiv.2010.15970", "publisher": "arXiv", "publication_date": "2020-10-29" }, { "id": "authors:a1bwb-qsn19", "collection": "authors", "collection_id": "a1bwb-qsn19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181203-093154510", "type": "monograph", "title": "Mass Hierarchy and Vacuum Energy", "author": [ { "family_name": "Cheung", "given_name": "Clifford", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Saraswat", "given_name": "Prashant", "clpid": "Saraswat-P" } ], "abstract": "A hierarchically small weak scale does not generally coincide with enhanced\nsymmetry, but it may still be exceptional with respect to vacuum energy. By\nanalyzing the classical vacuum energy as a function of parameters such as the\nHiggs mass, we show how near-criticality, i.e. fine-tuning, corresponds\nuniversally to boundaries where the vacuum energy transitions from exactly flat\nto concave down. In the presence of quantum corrections, these boundary regions\ncan easily be perturbed to become maxima of the vacuum energy. After\nintroducing a dynamical scalar field $\\phi$ which scans the Higgs sector\nparameters, we propose several possible mechanisms by which this field could be\nlocalized to the maximum. One possibility is that the $\\phi$ potential has many\nvacua, with those near the maximum vacuum energy expanding faster during a long\nperiod of cosmic inflation and hence dominating the volume of the Universe.\nAlternately, we describe scenarios in which vacua near the maximum could be\nanthropically favored, due to selection of the late-time cosmological constant\nor dark matter density. Independent of these specific approaches, the physical\nvalue of the weak scale in our proposal is generated naturally and dynamically\nfrom loops of heavy states coupled to the Higgs. These states are predicted to\nbe a loop factor heavier than in models without this mechanism, avoiding\ntension with experimental null results.", "doi": "10.48550/arXiv.1811.12390", "publisher": "arXiv", "publication_date": "2018-11-29" }, { "id": "authors:shf3c-qes17", "collection": "authors", "collection_id": "shf3c-qes17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170815-101847186", "type": "monograph", "title": "TASI Lectures on Scattering Amplitudes", "author": [ { "family_name": "Cheung", "given_name": "Clifford", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" } ], "abstract": "These lectures are a brief introduction to scattering amplitudes. We begin\nwith a review of basic kinematical concepts like the spinor helicity formalism,\nfollowed by a tutorial on bootstrapping tree-level scattering amplitudes.\nAfterwards, we discuss on-shell recursion relations and soft theorems,\nemphasizing their broad applicability to gravity, gauge theory, and effective\nfield theories. Lastly, we report on some of the new field theoretic structures\nwhich have emerged from the on-shell picture, focusing primarily on\ncolor-kinematics duality.", "doi": "10.48550/arXiv.1708.03872", "publisher": "arXiv", "publication_date": "2017-08-13" }, { "id": "authors:n4z3y-8qb65", "collection": "authors", "collection_id": "n4z3y-8qb65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160113-132530546", "type": "monograph", "title": "Broad Diphotons from Narrow States", "author": [ { "family_name": "An", "given_name": "Haipeng", "clpid": "An-Haipeng" }, { "family_name": "Cheung", "given_name": "Clifford", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Zhang", "given_name": "Yue", "clpid": "Zhang-Yue" } ], "abstract": "ATLAS and CMS have each reported a modest diphoton excess consistent with the\ndecay of a broad resonance at ~ 750 GeV. We show how this signal can arise in a\nweakly coupled theory comprised solely of narrow width particles. In\nparticular, if the decaying particle is produced off-shell, then the associated\ndiphoton resonance will have a broad, adjustable width. We present simplified\nmodels which explain the diphoton excess through the three-body decay of a\nscalar or fermion. Our minimal ultraviolet completion is a weakly coupled and\nrenormalizable theory of a singlet scalar plus a heavy vector-like quark and\nlepton. The smoking gun of this mechanism is an asymmetric diphoton peak\nrecoiling against missing transverse energy, jets, or leptons.", "doi": "10.48550/arXiv.1512.08378", "publisher": "arXiv", "publication_date": "2015-12-28" }, { "id": "authors:gdwtg-rx797", "collection": "authors", "collection_id": "gdwtg-rx797", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150731-184249348", "type": "monograph", "title": "Effectively Stable Dark Matter", "author": [ { "family_name": "Cheung", "given_name": "Clifford", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Sanford", "given_name": "David", "clpid": "Sanford-David" } ], "abstract": "We study dark matter (DM) which is cosmologically long-lived because of\nstandard model (SM) symmetries. In these models an approximate stabilizing\nsymmetry emerges accidentally, in analogy with baryon and lepton number in the\nrenormalizable SM. Adopting an effective theory approach, we classify DM models\naccording to representations of $SU(3)_C\\times SU(2)_L\\times U(1)_Y \\times\nU(1)_B\\times U(1)_L$, allowing for all operators permitted by symmetry, with\nweak scale DM and a cutoff at or below the Planck scale. We identify\nrepresentations containing a neutral long-lived state, thus excluding dimension\nfour and five operators that mediate dangerously prompt DM decay into SM\nparticles. The DM relic abundance is obtained via thermal freeze-out or, since\neffectively stable DM often carries baryon or lepton number, asymmetry sharing\nthrough the very operators that induce eventual DM decay. We also incorporate\nbaryon and lepton number violation with a spurion that parameterizes hard\nbreaking by arbitrary units. However, since proton stability precludes certain\nspurions, a residual symmetry persists, maintaining the cosmological stability\nof certain DM representations. Finally, we survey the phenomenology of\neffectively stable DM as manifested in probes of direct detection, indirect\ndetection, and proton decay.", "doi": "10.48550/arXiv.1507.00828", "publisher": "arXiv", "publication_date": "2015-07-03" }, { "id": "authors:9tbk0-j4d26", "collection": "authors", "collection_id": "9tbk0-j4d26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190621-155339603", "type": "monograph", "title": "Seesaw Spectroscopy at Colliders", "author": [ { "family_name": "Cheung", "given_name": "Clifford", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Hall", "given_name": "Lawrence J.", "clpid": "Hall-L-J" }, { "family_name": "Pinner", "given_name": "David", "clpid": "Pinner-D" } ], "abstract": "A low-scale neutrino seesaw may be probed or even reconstructed at colliders provided that supersymmetry is at the weak scale and the LSP is a sterile sneutrino. Because the neutrino Yukawa couplings are small, the NLSP is typically long-lived and thus a significant fraction of colored or charged NLSPs may stop in the detector material before decaying to the LSP and a charged lepton, gauge boson, or Higgs. For two-body NLSP decays, the energy spectrum of the visible decay product exhibits a monochromatic line for each sterile sneutrino which can be used to extract the sterile sneutrino masses and some or all entries of the neutrino Yukawa matrix modulo phases. Similar methods can be used to extract these parameters from the Dalitz plot in the case of three-body NLSP decays. Assuming that the sterile sneutrino and neutrino are roughly degenerate, one can confirm the existence of a neutrino seesaw by comparing these measured parameters to the observed active neutrino masses and mixing angles. Seesaw spectroscopy can also provide genuinely new information such as the value of \u03b8_(13), the nature of the neutrino mass hierarchy, and the presence of CP conservation in the neutrino sector. We introduce a weak-scale theory of leptogenesis that can be directly tested by these techniques.", "doi": "10.48550/arXiv.1103.3520", "publisher": "arXiv", "publication_date": "2011-03-17" } ]