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Figueroa, D. G., Pieroni, M., Ricciardone, A., & Simakachorn, P. (2024). Cosmological Background Interpretation of Pulsar Timing Array Data. Phys. Rev. Lett., 132(17), 171002–9pp.
Abstract: We discuss the interpretation of the detected signal by pulsar timing array (PTA) observations as a gravitational wave background of cosmological origin. We combine NANOGrav 15-years and EPTADR2new datasets and confront them against backgrounds from supermassive black hole binaries (SMBHBs), and cosmological signals from inflation, cosmic (super)strings, first-order phase transitions, Gaussian and non-Gaussian large scalar fluctuations, and audible axions. We find that scalar-induced, and to a lesser extent audible axion and cosmic superstring signals, provide a better fit than SMBHBs. These results depend, however, on modeling assumptions, so further data and analysis are needed to reach robust conclusions. Independently of the signal origin, the data strongly constrain the parameter space of cosmological signals, for example, setting an upper bound on primordial non-Gaussianity at PTA scales as jfnlj less than or similar to 2.34 at 95% C.L.
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Du, M. L., Filin, A., Baru, V., Dong, X. K., Epelbaum, E., Guo, F. K., et al. (2023). Role of Left-Hand Cut Contributions on Pole Extractions from Lattice Data: Case Study for Tcc(3875)+. Phys. Rev. Lett., 131(13), 131903–7pp.
Abstract: We discuss recent lattice data for the T-cc(3875)(+) state to stress, for the first time, a potentially strong impact of left-hand cuts from the one-pion exchange on the pole extraction for near-threshold exotic states. In particular, if the left-hand cut is located close to the two-particle threshold, which happens naturally in the DD* system for the pion mass exceeding its physical value, the effective-range expansion is valid only in a very limited energy range up to the cut and as such is of little use to reliably extract the poles. Then, an accurate extraction of the pole locations requires the one-pion exchange to be implemented explicitly into the scattering amplitudes. Our findings are general and potentially relevant for a wide class of hadronic near-threshold states.
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Foffa, S., Mastrolia, P., Sturani, R., Sturm, C., & Bobadilla, W. J. T. (2019). Static Two-Body Potential at Fifth Post-Newtonian Order. Phys. Rev. Lett., 122(24), 241605–6pp.
Abstract: We determine the gravitational interaction between two compact bodies up to the sixth power in Newton's constant, G(N), in the static limit. This result is achieved within the effective field theory approach to general relativity, and exploits a manifest factorization property of static diagrams which allows us to derive static post Newtonian (PN) contributions of (2n + 1) order in terms of lower order ones. We recompute in this fashion the 1PN and 3PN static potential, and present the novel 5PN contribution.
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Pierre Auger Collaboration(Abraham, J. et al), & Pastor, S. (2010). Measurement of the Depth of Maximum of Extensive Air Showers above 10(18) eV. Phys. Rev. Lett., 104(9), 091101–7pp.
Abstract: We describe the measurement of the depth of maximum, X-max, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10(18) eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +/- 35-21) g/cm(2)/decade below 10(18.24) +/- (0.05) eV, and d24 +/- 3 g/cm(2)/ecade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm(2). The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.
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Gessner, M., & Smerzi, A. (2023). Hierarchies of Frequentist Bounds for Quantum Metrology: From Cramer-Rao to Barankin. Phys. Rev. Lett., 130(26), 260801–6pp.
Abstract: We derive lower bounds on the variance of estimators in quantum metrology by choosing test observables that define constraints on the unbiasedness of the estimator. The quantum bounds are obtained by analytical optimization over all possible quantum measurements and estimators that satisfy the given constraints. We obtain hierarchies of increasingly tight bounds that include the quantum Cramer-Rao bound at the lowest order. In the opposite limit, the quantum Barankin bound is the variance of the locally best unbiased estimator in quantum metrology. Our results reveal generalizations of the quantum Fisher information that are able to avoid regularity conditions and identify threshold behavior in quantum measurements with mixed states, caused by finite data.
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Figueroa, D. G., Raatikainen, S., Rasanen, S., & Tomberg, E. (2021). Non-Gaussian Tail of the Curvature Perturbation in Stochastic Ultraslow-Roll Inflation: Implications for Primordial Black Hole Production. Phys. Rev. Lett., 127(10), 101302–7pp.
Abstract: We consider quantum diffusion in ultraslow-roll (USR) inflation. Using the Delta N formalism, we present the first stochastic calculation of the probability distribution P(R) of the curvature perturbation during USR. We capture the nonlinearity of the system, solving the coupled evolution of the coarse-grained background with random kicks from the short wavelength modes, simultaneously with the mode evolution around the stochastic background. This leads to a non-Markovian process from which we determine the highly non-Gaussian tail of P(R). Studying the production of primordial black holes in a viable model, we find that stochastic effects during USR increase their abundance by a factor of similar to 10(5) compared with the Gaussian approximation.
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Boiron, D., Fabbri, A., Larre, P. E., Pavloff, N., Westbrook, C. I., & Zin, P. (2015). Quantum Signature of Analog Hawking Radiation in Momentum Space. Phys. Rev. Lett., 115(2), 025301–5pp.
Abstract: We consider a sonic analog of a black hole realized in the one-dimensional flow of a Bose-Einstein condensate. Our theoretical analysis demonstrates that one-and two-body momentum distributions accessible by present-day experimental techniques provide clear direct evidence (i) of the occurrence of a sonic horizon, (ii) of the associated acoustic Hawking radiation, and (iii) of the quantum nature of the Hawking process. The signature of the quantum behavior persists even at temperatures larger than the chemical potential.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Combination of Tevatron Searches for the Standard Model Higgs Boson in the W+W- Decay Mode. Phys. Rev. Lett., 104(6), 061802–11pp.
Abstract: We combine searches by the CDF and D0 Collaborations for a Higgs boson decaying to W+W-. The data correspond to an integrated total luminosity of 4.8 (CDF) and 5.4 (D0) fb(-1) of p (p) over bar collisions at root s = 1.96 TeV at the Fermilab Tevatron collider. No excess is observed above background expectation, and resulting limits on Higgs boson production exclude a standard model Higgs boson in the mass range 162-166 GeV at the 95% C.L.
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Campanario, F., Figy, T. M., Platzer, S., & Sjodahl, M. (2013). Electroweak Higgs Boson Plus Three Jet Production at Next-to-Leading-Order QCD. Phys. Rev. Lett., 111(21), 211802–4pp.
Abstract: We calculate next-to-leading order (NLO) QCD corrections to electroweak Higgs boson plus three jet production. Both vector boson fusion (VBF) and Higgs-strahlung type contributions are included along with all interferences. The calculation is implemented within the MATCHBOX NLO framework of the HERWIG++ event generator.
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Blanton, T. D., Romero-Lopez, F., & Sharpe, S. R. (2020). I=3 Three-Pion Scattering Amplitude from Lattice QCD. Phys. Rev. Lett., 124(3), 032001–7pp.
Abstract: We analyze the spectrum of two- and three-pion states of maximal isospin obtained recently for isosymmetric QCD with pion mass M approximate to 200 MeV in Horz and Hanlon, [Phys. Rev. Lett. 123, 142002 (2019)]. Using the relativistic three-particle quantization condition, we find similar to 2 sigma evidence for a nonzero value for the contact part of the 3 pi(+) (I = 3) scattering amplitude. We also compare our results to leading-order chiral perturbation theory. We find good agreement at threshold and some tension in the energy dependent part of the 3 pi(+) scattering amplitude. We also find that the 2 pi(+) (I = 2) spectrum is fit well by an s-wave phase shift that incorporates the expected Adler zero.
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