63 research outputs found
Coupling QCD-scale axion-like particles to gluons
We present a novel data-driven method for determining the hadronic
interaction strengths of axion-like particles (ALPs) with QCD-scale masses.
Using our method, it is possible to calculate the hadronic production and decay
rates of ALPs, along with many of the largest ALP decay rate to exclusive final
states. To illustrate the impact on QCD-scale ALP phenomenology, we consider
the scenario where the ALP-gluon coupling is dominant over the ALP coupling to
photons, electroweak bosons, and all fermions for GeV. We emphasize, however, that our method can easily be
generalized to any set of ALP couplings to SM particles. Finally, using the
approach developed here, we provide calculations for the branching fractions of
decays, i.e. decays into two vector mesons, which are
consistent with the known experimental values.Comment: 19 pages, 7 figures; v3 Fig 4 updated to account for a small change
in the limit taken from [1903.03586
and leptonic decays as probes of solutions to the puzzle
Experimental measurements of the ratios () show a
deviation from the Standard Model prediction. In the absence of
light right-handed neutrinos, a new physics contribution to
decays necessarily modifies also and/or transitions. These contributions lead to violation of lepton
flavor universality in, respectively, and leptonic decays. We
analyze the constraints resulting from measurements of the leptonic
vector-meson decays on solutions to the puzzle. Available data
from BaBar and Belle can already disfavor some of the new physics explanations
of this anomaly. Further discrimination can be made by measuring
in the upcoming Belle II experiment.Comment: Version published in JHEP, 17 pages, 7 figure
Photoproduction of axion-like particles
We explore the sensitivity of photon-beam experiments to axion-like particles
(ALPs) with QCD-scale masses whose dominant coupling to the Standard Model is
either to photons or gluons. We introduce a novel data-driven method that
eliminates the need for knowledge of nuclear form factors or the photon-beam
flux when considering coherent Primakoff production off a nuclear target, and
show that data collected by the PrimEx experiment could substantially improve
the sensitivity to ALPs with GeV. Furthermore,
we explore the potential sensitivity of running the GlueX experiment with a
nuclear target and its planned PrimEx-like calorimeter. For the case where the
dominant coupling is to gluons, we study photoproduction for the first time,
and predict the future sensitivity of the GlueX experiment using its nominal
proton target. Finally, we set world-leading limits for both the ALP-gluon
coupling and the ALP-photon coupling based on public mass plots.Comment: 17 pages, 7 figures; v3 corrected PrimEx results for luminosity
error; v2 added missing factor when drawing the GlueX limits on the ALP-gluon
coupling, fixed convention discrepancy in the SeaQuest ALP-photon limits,
other minor edit
Dark Radiation from Neutrino Mixing after Big Bang Nucleosynthesis
A light ( MeV) dark fermion mixing with the Standard
Model neutrinos can naturally equilibrate with the neutrinos via oscillations
and scattering. In the presence of dark sector interactions, production of dark
fermions is generically suppressed above BBN, but then enhanced at later times.
Over much of the parameter space, we find that the dark sector equilibrates,
even for mixing angles as small as , and equilibration
occurs at which is naturally at most a few orders of magnitude above the
dark fermion mass. The implications of this are twofold: one, that light states
are often only constrained by the CMB and LSS without leaving an imprint on
BBN, and two, that sectors which equilibrate before recombination will
typically have a mass threshold before recombination, as well. This can result
in dark radiation abruptly transitioning from non-interacting to interacting,
or vice-versa, a ``step'' in the amount of dark radiation, and dark matter with
similar transitions in its interactions, all of which can leave important
signals in the CMB and LSS, and may be relevant for cosmological tensions in
observables such as or . Minimal models leave an unambiguous imprint
on the CMB above the sensitivity of upcoming experiments.Comment: 6 pages, 2 figure
Spontaneous CP Violation and Horizontal Symmetry in the MSSM: Toward Lepton Flavor Naturalness
We study the contributions of supersymmetric models with a horizontal
symmetry and only spontaneous CP breaking to various lepton flavor observables,
such as and the electron electric dipole moment. We show that
both a horizontal symmetry and a lack of explicit CP violation can alleviate
the existing bounds from such observables. The undetermined
coefficients in such mass matrix models muddle the interpretation of the bounds
from various flavor observables. To overcome this, we define a new fine-tuning
measure for different observables in such setups. This allows us to study how
naturally the observed IR flavor observables can emerge from a given mass
matrix model. We use our flavor-naturalness measure in study of our
supersymmetric models and quantify the degree of fine tuning required by the
bounds from various lepton flavor observables at each mass scale of sleptons,
neutralinos, and charginos.Comment: Minor changes to how random numbers are generated. Conclusions
unchanged. Version published in JHEP. 31+18 Pages. 9 Figures. 6 Table
Watermarking Cryptographic Capabilities
A watermarking scheme for programs embeds some information called a mark into a program while preserving its functionality. No adversary can remove the mark without damaging the functionality of the program. In this work, we study the problem of watermarking various cryptographic programs such as pseudorandom function (PRF) evaluation, decryption, and signing. For example, given a PRF F, we create a marked program C~ that evaluates F(). An adversary that gets C~ cannot come up with any program C* in which the mark is removed but which still evaluates the PRF correctly on even a small fraction of the inputs.
The work of Barak, Goldreich, Impagliazzo, Rudich, Sahai, Vadhan, and Yang (CRYPTO\u2701 and Journal of ACM 59(2)) shows that, assuming indistinguishability obfuscation (iO), such watermarking is impossible if the marked program C~ evaluates the original program with perfect correctness. In this work we show that, assuming iO, such watermarking is possible if the marked program C~ is allowed to err with even a negligible probability, which would be undetectable to the user.
Our watermarking schemes are public key, meaning that we use a secret marking key to embed marks in programs, and a public detection key that allows anyone to detect marks in programs. Our schemes are secure against chosen program attacks where the adversary is given oracle access to the marking functionality. We emphasize that our security notion of watermark non-removability considers arbitrary adversarial strategies to modify the marked program, in contrast to the prior works (Nishimaki, EUROCRYPT \u2713)
A step in understanding the Hubble tension
As cosmological data have improved, tensions have arisen. One such tension is the difference between the locally measured Hubble constant H 0 and the value inferred from the cosmic microwave background (CMB). Interacting radiation has been suggested as a solution, but studies show that conventional models are precluded by high- ℓ CMB polarization data. It seems at least plausible that a solution may be provided by related models that distinguish between high- and low- ℓ multipoles. When interactions of strongly-coupled radiation are mediated by a force carrier that becomes nonrelativistic, the dark radiation undergoes a “step” in which its relative energy density increases as the mediator deposits its entropy into the lighter species. If this transition occurs while CMB-observable modes are inside the horizon, high- and low- ℓ peaks are impacted differently, corresponding to modes that enter the horizon before or after the step. These dynamics are naturally packaged into the simplest supersymmetric theory, the Wess-Zumino model, with the mass of the scalar mediator near the eV scale. We investigate the cosmological signatures of such Wess-Zumino dark radiation (WZDR) and find that it provides an improved fit to the CMB alone, favoring larger values of H 0 . If supernovae measurements from the SH0ES Collaboration are also included in the analysis, the inferred value of H 0 is yet larger, but the preference for dark radiation and the location of the transition is left nearly unchanged. Utilizing a standardized set of measures, we compare to other models and find that WZDR is among the most successful at addressing the H 0 tension and is the best of those with a Lagrangian formulation.https://arxiv.org/pdf/2111.00014Accepted manuscrip
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