Mon·Feb 21, 2022Monday·February 21, 2022

1. 01*

   Mixing Particle Production for Relaxion Mechanism

   Tanech Klangburam🇹🇭 · Areef Waeming🇹🇭 · Predee Tantirangsri🇹🇭 · Daris Samart🇹🇭 · Chakrit Pongkitivanichkul🇹🇭

   We consider the production of two heavy gauge bosons as a relaxation stopping mechanism. In this work, we analyse the conditions for a tachyonic mode for a linear combination of gauge bosons and show that the criteria are significantly different than the single gauge boson case. Moreover, the implementation of the mechanism on the $U(1{)}^{\prime }$ model is demonstrated. We discuss various constraints for the relaxion mechanism. The phenomenology of the heavy gauge boson is also explored. We finally show a benchmark point of parameter space considering all constraints from relaxion and the $U(1{)}^{\prime }$ mixing sector.

   hep-phhep-thJHEP(2022)·1 citation
2. 02*

   Do direct detection experiments constrain axionlike particles coupled to electrons?

   Ricardo Z. Ferreira🇪🇸 · M.C. David Marsh🇸🇪 · Eike Müller🇸🇪

   Several laboratory experiments have published limits on axionlike particles (ALPs) with feeble couplings to electrons and masses in the keV-MeV range, under the assumption that such ALPs comprise the dark matter. We note that ALPs decay radiatively into photons, and show that for a large subset of the parameter space ostensibly probed by these experiments, the lifetime of the ALPs is shorter than the age of the universe. Such ALPs cannot consistently make up the dark matter, which significantly affects the interpretation of published limits from GERDA, Edelweiss-III, SuperCDMS and Majorana. Moreover, constraints from gamma-ray and X-ray astronomy exclude an even wider range of the ALP-electron coupling, and supersede all current experimental limits on dark matter ALPs in the 6 keV to 1 MeV mass range. These conclusions are rather model-independent, and can only be avoided at the expense of significant fine-tuning in theories where the ALP has additional couplings to other particles.

   hep-phhep-exPRL(2022)·37 citations
3. 03*

   Renormalons in a scalar self interacting theory: thermal, thermomagnetic and thermoelectric corrections for all values of temperature

   M. Loewe🇨🇱 · R. Zamora🇨🇱

   In this article we revisit the discussion of renormalons in the frame of a scalar self-interacting $\lambda {\varphi }^4$ theory in the presence of thermomagnetic effects, i.e magnetic and thermal effects. Our results for the evolution of the residues is now given by an explicit analytic expression, valid for all values of temperature, without the necessity of separating the discussion in a low- and a high temperature region analyses. We carry out the same discussion for the case of an external constant electric field, obtaining also in this case an analytic expression for the whole range o temperature. In both cases, the location of the poles in the Borel plane does not change with respect to the vacuum case. Their residues, however, acquire a dependence on temperature and the external field. Results are presented for the evolution of residues in the thermomagnetic and thermoelectric cases. We show a comparison with our previous results in the thermomagnetic case, presenting also in detail the mathematical techniques needed for our analytic expressions to be valid in the whole range of temperature.

   hep-phhep-thPRD(2022)·13 citations
4. 04*

   Axial-vector transition form factors of the baryon octet to the baryon decuplet with flavor SU(3) symmetry breaking

   Jung-Min Suh🇰🇷 · Yu-Son Jun🇰🇷 · Hyun-Chul Kim🇰🇷

   We investigate the axial-vector transition form factors of the baryon octet to the baryon decuplet within the framework of the chiral quark-soliton model, with the effects of flavor SU(3) symmetry breaking included. We consider the rotational $1/N_c$ corrections and regard the strange current quark mass as a perturbation. We compare the present results for the $\Delta \to N$ axial-vector transition with those from other models and lattice QCD. We also compute all possible axial-vector transitions from the baryon decuplet to the octet with the strangeness changed, i.e., $|\Delta S|=1$. We obtain the value of the essential form factor $C_5^A$ for the $\Delta \to N$ axial-vector transition at the zero momentum transfer ($Q^2=0$). Furthermore, the present results are in good agreement with those fitted with the T2K data. We extract the value of the axial-vector mass $M_A$ compared to the data.

   hep-phhep-exhep-latPRD(2022)·6 citations
5. 05*

   Fine-Tuning in the 2HDM

   A. Bernal🇪🇸 · J. A. Casas🇪🇸 · J.M. Moreno🇪🇸

   The Two-Higgs Doublet Model (2HDM) is one of the most popular and natural extensions of the Higgs sector; but it has two potential fine-tuning problems, related to the electroweak (EW) breaking and the requirement of alignment with the SM Higgs boson. We have quantified the fine-tunings obtaining analytical expressions, both in terms of the initial 2HDM parameters and the physical ones (masses, mixing angles, etc.). We also provide simple approximate expressions. We have taken into account that the fine-tunings are not independent and removed the "double counting" by projecting the variations of the alignment onto the constant-${\mathrm{v}}^2$ hypersurface. The EW and the alignment fine-tunings become severe in different, even opposite, regions of the parameter space, namely in the regimes of large and small extra-Higgs masses, respectively; emerging an intermediate region, $500\mathrm{GeV}\le \{m_H,m_A,m_{H^{\pm }}\}\le 700\mathrm{GeV}$, where both are acceptably small. We also discuss a remarkable trend that is not obvious at first glance. Namely, for large $\tan \beta$ both the EW and the alignment fine-tunings become mitigated. In consequence, the 2HDM becomes quite natural for $\tan \beta \ge \mathcal{O}(10)$, even if $m_H,m_A,m_{H^{\pm }}$ are as large as 1500 GeV. We explain why this is not the case for the 2HDM stemming from supersymmetry. We have illustrated all these trends by numerically analyzing several representative scenarios.

   hep-phEPJC(2022)·4 citations
6. 06*

   Real-time observables from Euclidean thermal correlation functions

   Peter Lowdon🇩🇪 · Ralf-Arno Tripolt🇩🇪

   In this work we apply a local quantum field theory approach in order to analyse the connection between real-time observables and Euclidean thermal correlation functions. In particular, using data generated from the functional renormalisation group in the quark-meson model, we demonstrate that in-medium effects can be directly extracted from the spatial momentum dependence of the Euclidean propagators, in contrast to conventional approaches, which rely on the reconstruction from different Matsubara frequencies. As an application, we determine the analytic features that arise from the discrete spectral contribution to the pion correlation function, and calculate the non-perturbative shear viscosity arising from these states.

   hep-phhep-thnucl-thPRD(2022)·7 citations
7. 07*

   Nonleptonic two-body decays of ${\Lambda }_b\to {\Lambda }_c\pi ,{\Lambda }_{c}K$ in the perturbative QCD approach

   Chao-Qi Zhang🇨🇳 · Jia-Ming Li🇨🇳 · Meng-Kun Jia🇨🇳 · Zhou Rui🇨🇳

   We study the color-allowed ${\Lambda }_b\to {\Lambda }_c\pi ,{\Lambda }_{c}K$ decays in the perturbative QCD approach (PQCD) to lowest order in strong coupling constant ${\alpha }_s$. Both the factorizable and nonfactorizable contributions are taken into account in our calculations. It is found that these processes are dominated by the factorizable contributions, while the important nonfactorizable contributions can enhance the branching ratios by about 30$\%$. The decay branching ratios are predicted to be $\mathcal{B}({\Lambda }_b\to {\Lambda }_c\pi )=6.7_{-3.8}^{+4.1}\times 10^{-3}$ and $\mathcal{B}({\Lambda }_b\to {\Lambda }_{c}K)=5.0_{-3.0}^{+4.0}\times 10^{-4}$, where the uncertainties arise from the baryon light-cone distribution amplitudes (LCDAs), the heavy charm quark and charmed baryon masses, and the hard scales. It is shown that the asymmetry parameters in the two decays are approximately equal to -1, which is expected as in the heavy quark limit and the soft meson limit. Our predictions are consistent with the recent experimental data within errors. The obtained numerical results are also compared to those in the other theoretical approaches when they are available.

   hep-phPRD(2022)·22 citations
8. 08*

   Indirect search of Heavy Neutral Leptons using the DUNE Near Detector

   S. Carbajal🇵🇪 · A. M. Gago🇵🇪

   We evaluate the potential of the DUNE Near Detector (DUNEND) for establishing bounds for heavy neutral leptons (HNL). This is achieved by studying how the presence of HNLs affects the production rates of active neutrinos, therefore, creating a deficit in the neutrino charged current (CC) events at the LArTPC of the DUNEND. The estimated bounds on HNLs are calculated for masses between 1 eV and 500 MeV. We consider 10 years of operation (5 in neutrino and antineutrino mode) and obtain limits of $|U_{\mu 4}{|}^2<9\times 10^{-3}(4\times 10^{-2})$ and $|U_{e4}{|}^2<7\times 10^{-3}(3\times 10^{-2})$ for masses below 10 MeV and a 5\%(20\%) overall normalization uncertainty in the neutrino charged current event rates prediction. These limits, within the region of masses below 2(10) MeV, are better than those that can be achieved by DUNE direct searches for the case of a 5\%(20\%) uncertainty. When a conservative 20\% uncertainty is present, our limits can only improve current constraints on $|U_{e4}{|}^2$ by up to a factor of 3 in a small region around 5 eV and set limits on $|U_{\mu 4}{|}^2$ in a mass region free of constraints (40 eV - 1 MeV).

   hep-phhep-exFront.in Phys.(2024)·8 citations
9. 09*

   Archetypal Factorization and Gluon Poles in semi-exclusive reactions

   I.V. Anikin🇷🇺 · L. Szymanowski🇵🇱

   Within the archetypal factorization procedure, we study the gluon pole contributions manifesting in the nucleon-lepton hard processes of hadron production. We prove the dominant role of gluon pole contributions in the processes of such kind. We analyse the different sources of complexity associated with the gluon pole functions. As a practical application, we derive a new single spin asymmetry related directly to the gluon poles which can be studied experimentally.

   hep-phPTEP(2022)·5 citations
10. 10*

    The sensitivity of $\mu \to e$ processes to $\tau$ flavour change

    Marco Ardu🇫🇷 · Sacha Davidson🇫🇷 · Martin Gorbahn🇬🇧

    Transforming a $\mu$ to a $\tau$, then the $\tau$ to to an $e$, results in $\mu \to e$. In an EFT framework, we explore the sensitivity of $\mu \to e$ observables to products of $(\mu \to \tau )\times (\tau \to e)$ interactions, and show that the exceptional sensitivity of upcoming $\mu \to e$ experiments could allow to probe parameter space beyond the reach of upcoming $\tau \to l$ searches in Higgs, $\tau$ and $B$ decays. We describe the $\tau \to l$ interactions as dimension six operators in the SM EFT, identify pairs of them giving interesting contributions to $\mu \to e$ processes, and obtain the anomalous dimensions mixing those pairs into dimension eight $\mu \to e$ operators. We find that $\mu \to e$ processes are sensitive to $\tau$ flavour-changing $B$ decays at rates comparable to current $B$ anomalies, but cannot reduce rates -- as appropriate in many current $B$ anomalies -- because they do not interfere with the SM.

    hep-phPRD(2022)·20 citations
11. 11*

    The ALPs from the Top: Searching for long lived axion-like particles from exotic top decays

    Adrian Carmona🇪🇸 · Fatemeh Elahi🇩🇪 · Christiane Scherb🇩🇪 · Pedro Schwaller🇩🇪

    We propose a search for long lived axion-like particles (ALPs) in exotic top decays. Flavour-violating ALPs appear as low energy effective theories for various new physics scenarios such as t-channel dark sectors or Froggatt-Nielsen models. In this case the top quark may decay to an ALP and an up- or charm-quark. For masses in the few GeV range, the ALP is long lived across most of the viable parameter space, suggesting a dedicated search. We propose to search for these long lived ALPs in $t\bar{t}$ events, using one top quark as a trigger. We focus on ALPs decaying in the hadronic calorimeter, and show that the ratio of energy deposits in the electromagnetic and hadronic calorimeters as well as track vetoes can efficiently suppress Standard Model backgrounds. Our proposed search can probe exotic top branching ratios smaller than $10^{-4}$ with a conservative strategy at the upcoming LHC run, and potentially below the $10^{-7}$ level with more advanced methods. Finally we also show that measurements of single top production probe these branching ratios in the very short and very long lifetime limit at the $10^{-3}$ level.

    hep-phJHEP(2022)·34 citations
12. 12*

    Requirements on common solutions to the LSND and MiniBooNE excesses: a post-MicroBooNE study

    Waleed Abdallah🇪🇬 · Raj Gandhi🇮🇳 · Samiran Roy🇮🇳

    The strong statistical significance of an observed electron-like event excess in the MiniBooNE (MB) experiment, along with an earlier similar excess seen in the Liquid Scintillator Neutrino Detector (LSND), when interpreted in conjunction with recent MicroBooNE results may have brought us to the cusp of new physics discoveries. This has led to many attempts to understand these observations, both for each experiment individually and in conjunction, via physics beyond the Standard Model (SM). We provide an overview of the current situation, and discuss three major categories under which the many proposals for new physics fall. The possibility that the same new, non-oscillation physics explains both anomalies leads to new restrictions and requirements. An important class of such common solutions, which we focus on in this work, consists of a heavy $\mathcal{O}$(MeV$-$sub-GeV) sterile neutral fermion produced in the detectors, (via up-scattering of the incoming muon neutrinos), and subsequently decaying to photons or $e^{+}{e}^{-}$ pairs which mimic the observed signals. Such solutions are subject to strong demands from a) cross section requirements which would yield a sufficient number of total events in both LSND and MB, b) requirements imposed by the measured energy and angular distributions in both experiments and finally, c) consistency and compatibility of the new physics model and its particle content with other bounds from a diverse swathe of particle physics experiments. We find that these criteria often pull proposed solutions in different directions, and stringently limit the viable set of proposals which could resolve both anomalies. Our conclusions are relevant for both the general search for new physics and for the ongoing observations and analyses of the MicroBooNE experiment.

    hep-phhep-exJHEP(2022)·17 citations
13. 13*

    Ephemeral Learning -- Augmenting Triggers with Online-Trained Normalizing Flows

    Anja Butter🇩🇪 · Sascha Diefenbacher🇩🇪 · Gregor Kasieczka🇩🇪 · Benjamin Nachman🇺🇸 · Tilman Plehn🇩🇪 · David Shih🇺🇸 · Ramon Winterhalder🇧🇪

    The large data rates at the LHC require an online trigger system to select relevant collisions. Rather than compressing individual events, we propose to compress an entire data set at once. We use a normalizing flow as a deep generative model to learn the probability density of the data online. The events are then represented by the generative neural network and can be inspected offline for anomalies or used for other analysis purposes. We demonstrate our new approach for a toy model and a correlation-enhanced bump hunt.

    hep-phhep-exphysics.data-anSciPost Phys.(2022)·20 citations
14. 14*

    Pancosmic Relativity and Nature's Hierarchies

    Nemanja Kaloper🇺🇸

    We define `third derivative' General Relativity, by promoting the integration measure in Einstein-Hilbert action to be an arbitrary $4$-form field strength. We project out its local fluctuations by coupling it to another $4$-form field strength. This ensures that the gravitational sector contains only the usual massless helicity-2 propagating modes. Adding the charges to these $4$-forms allows for discrete variations of the coupling parameters of conventional General Relativity: $G_N,\Lambda ,H_0$, and even $⟨\mathtt{Higgs}⟩$ are all variables which can change by jumps. Hence de Sitter is unstable to membrane nucleation. Using this instability we explain how the cosmological constant problem can be solved. The scenario utilizes the idea behind the irrational axion, but instead of an axion it requires one more $4$-form field strength and corresponding charged membranes. When the membrane charges satisfy the constraint $\frac{2{\kappa }_{\mathtt{eff}}^2{\kappa }^2|{\mathcal{Q}}_i|}{3{\mathcal{T}}_i^2}<1$, the theory which ensues exponentially favors a huge hierarchy $\Lambda /{\text{mpl}}^4\ll 1$ instead of $\Lambda /{\text{mpl}}^4\simeq 1$. The discharges produce the distribution of the values of $\Lambda$ described by the saddle point approximation of the Euclidean path integral.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2022)·20 citations
15. 15*

    How do Magnetic Field Models Affect Astrophysical Limits on Light Axion-like Particles? An X-ray Case Study with NGC 1275

    James H. Matthews🇬🇧 · Christopher S. Reynolds🇬🇧 · M. C. David Marsh🇸🇪 · Júlia Sisk-Reynés🇬🇧 · Payton E. Rodman🇬🇧

    Axion-like particles (ALPs) are a well-motivated extension to the standard model of particle physics, and X-ray observations of cluster-hosted AGN currently place the most stringent constraints on the ALP coupling to electromagnetism, $g_{a\gamma }$, for very light ALPs ($m_a\lesssim 10^{-11}$ eV). We revisit limits obtained by Reynolds et al. (2020) using Chandra X-ray grating spectroscopy of NGC 1275, the central AGN in the Perseus cluster, examining the impact of the X-ray spectral model and magnetic field model. We also present a new publicly available code, ALPro, which we use to solve the ALP propagation problem. We discuss evidence for turbulent magnetic fields in Perseus and show that it can be important to resolve the magnetic field structure on scales below the coherence length. We re-analyse the NGC 1275 X-ray spectra using an improved data reduction and baseline spectral model. We find the limits are insensitive to whether a partially covering absorber is used in the fits. At low $m_a$ ($m_a\lesssim 10^{-13}$ eV), we find marginally weaker limits on $g_{a\gamma }$ (by $0.1-0.3$ dex) with different magnetic field models, compared to Model B from Reynolds et al. (2020). A Gaussian random field (GRF) model designed to mimic $\sim 50$ kpc scale coherent structures also results in only slightly weaker limits. We conclude that the existing Model B limits are robust assuming that ${\beta }_{\mathrm{pl}}\approx 100$, and are insensitive to whether cell-based or GRF methods are used. However, astrophysical uncertainties regarding the strength and structure of cluster magnetic fields persist, motivating high sensitivity RM observations and tighter constraints on the radial profile of ${\beta }_{\mathrm{pl}}$.

    ↳ astro-ph.HEastro-ph.COhep-phApJ(2022)·36 citations
16. 16*

    Warped compactifications and holographic duality

    Joel Giedt🇺🇸

    We review warped compactifications of superstring theory with some attention to the limit in which these resemble "bottom-up" phenomenological models. In addition to some discussion of the original Klebanov-Witten and Klebanov-Strassler set-ups, we also touch on various generalizations of the geometry that have been considered. Various other systems with a holographic duality are also briefly reviewed. The point of this latter exploration is to illustrate how far beyond the standard AdS(5) x S(5) set-up things have moved over the years.

    ↳ hep-thhep-phInt.J.Mod.Phys.A(2022)·1 citation
17. 17*

    Taylor expansions and Padé approximants for cumulants of conserved charge fluctuations at non-vanishing chemical potentials

    D. Bollweg🇺🇸 · J. Goswami🇩🇪 · O. Kaczmarek🇩🇪 · F. Karsch🇩🇪 · Swagato Mukherjee🇺🇸 · P. Petreczky🇺🇸 · C. Schmidt🇩🇪 · P. Scior🇺🇸

    Using high statistics datasets generated in (2+1)-flavor QCD calculations at finite temperature we present results for low order cumulants of net baryon-number fluctuations at non-zero values of the baryon chemical potential. We calculate Taylor expansions for the pressure (zeroth order cumulant), net baryon-number density (first order cumulant) and the variance of the distribution on net-baryon number fluctuations (second order cumulant). We obtain series expansions from an eighth order expansion of the pressure and compare these to diagonal Padé approximants. This allows us to estimate the range of values for the baryon chemical potential in which these expansions are reliable. We find ${\mu }_B/T\le 2.5$, $2.0$ and $1.5$ for the zeroth, first and second order cumulants, respectively. We furthermore, construct estimators for the radius of convergence of the Taylor series of the pressure. In the vicinity of the pseudo-critical temperature, $T_{pc}\simeq 156.5$ MeV, we find ${\mu }_B/T\gtrsim 2.9$ at vanishing strangeness chemical potential and somewhat larger values for strangeness neutral matter. These estimates are temperature dependent and range from ${\mu }_B/T\gtrsim 2.2$ at $T=135$ MeV to ${\mu }_B/T\gtrsim 3.2$ at $T=165$ MeV. The estimated radius of convergences is the same for any higher order cumulant.

    ↳ hep-lathep-phnucl-thPRD(2022)·115 citations
18. 18*

    Testing the boundaries: Normalizing Flows for higher dimensional data sets

    Humberto Reyes-Gonzalez🇮🇹 · Riccardo Torre🇮🇹

    Normalizing Flows (NFs) are emerging as a powerful class of generative models, as they not only allow for efficient sampling, but also deliver, by construction, density estimation. They are of great potential usage in High Energy Physics (HEP), where complex high dimensional data and probability distributions are everyday's meal. However, in order to fully leverage the potential of NFs it is crucial to explore their robustness as data dimensionality increases. Thus, in this contribution, we discuss the performances of some of the most popular types of NFs on the market, on some toy data sets with increasing number of dimensions.

    ↳ stat.MLcs.LGhep-phJ.Phys.Conf.Ser.(2023)·4 citations
19. 19*

    Chiral plasma instability and inverse cascade from nonequilibrium left-handed neutrinos in core-collapse supernovae

    Jin Matsumoto🇯🇵 · Naoki Yamamoto🇯🇵 · Di-Lun Yang🇹🇼

    We show that the backreaction of left-handed neutrinos out of equilibrium on the matter sector induces an electric current proportional to a magnetic field even without a chiral imbalance for electrons in core-collapse supernovae. We derive the transport coefficient of this effect based on the recently formulated chiral radiation transport theory for neutrinos. This chiral electric current generates a strong magnetic field via the so-called chiral plasma instability, which could provide a new mechanism for the strong and stable magnetic field of magnetars. We also numerically study the physical origin of the inverse cascade of the magnetic energy in the magnetohydrodynamics including this current. Our results indicate that incorporating the chiral effects of neutrinos would drastically modify the hydrodynamic evolutions of supernovae, which may also be relevant to the explosion dynamics.

    ↳ astro-ph.HEhep-phnucl-thPRD(2022)·23 citations
20. 20*

    Massive neutrino self-interactions with a light mediator in cosmology

    Jorge Venzor🇲🇽 · Gabriela Garcia-Arroyo🇲🇽 · Abdel Pérez-Lorenzana🇲🇽 · Josue De-Santiago🇲🇽

    Nonstandard self-interactions can alter the evolution of cosmological neutrinos, mainly by damping free streaming, which should leave traces in cosmological observables. Although overall effects are opposite to those produced by neutrino mass and a larger $N_{\mathrm{eff}}$, they cannot be totally canceled by these last. We harness cosmological data that includes Cosmic Microwave Background from Plank 2018, BAO measurements, local $H_0$, Ly-$\alpha$ and SNIa, to constrain massive neutrino self-interactions with a very light scalar mediator. We find that the effective coupling constant, at the 95\% C.L., should be $g_{\mathrm{eff}}<1.94\times 10^{-7}$ for only Planck 2018 data and $1.97\times 10^{-7}$ when Planck + BAO are considered. This bound relaxes to $2.27\times 10^{-7}$ ($2.3\times 10^{-7}$) for $H_0$ ($H_0$+SNe+Ly-$\alpha$) data. Using the Planck + BAO dataset, the $H_0$ tension lowers from 4.3$\sigma$ (for $\Lambda$CDM) to 3.2$\sigma$. The Akaike Information Criterion penalizes the self-interacting model due to its larger parameter space for Plank or Planck + BAO data, but favors the interacting model when we use local $H_0$ measurements. A somewhat larger value for $H_0$ is preferred when we include the whole data pool, which comes accompanied with a larger value of $N_{\mathrm{eff}}$ and a more constricted bound on $\Sigma m_{\nu }$.

    ↳ astro-ph.COhep-phPRD(2022)·33 citations
21. 21*

    On the complex structure of Yang-Mills theory

    Jan Horak🇩🇪 · Jan M. Pawlowski🇩🇪 · Nicolas Wink🇩🇪

    We consider the coupled set of spectral Dyson-Schwinger equations in Yang-Mills theory for ghost and gluon propagators, which gives us access to the ghost and gluon spectral functions. The set-up is used for a systematic analytic evaluation of the constraints on generalised spectral representations in Yang-Mills theory that are most relevant for informed spectral reconstructions. We also provide numerical results for the coupled set of spectral functions for a large range of potential mass gaps of the gluon, and discuss the limitations and extensions of the present work.

    ↳ hep-thhep-phSciPost Phys.Core(2025)·43 citations
22. 22*

    Hints of Early Dark Energy in Planck, SPT, and ACT data: new physics or systematics?

    Tristan L. Smith🇺🇸 · Matteo Lucca🇧🇪 · Vivian Poulin🇫🇷 · Guillermo F. Abellan🇫🇷 · Lennart Balkenhol🇦🇺 · Karim Benabed🇫🇷 · Silvia Galli🇫🇷 · Riccardo Murgia🇫🇷

    We investigate constraints on early dark energy (EDE) using ACT DR4, SPT-3G 2018, Planck polarization, and restricted Planck temperature data (at $\ell <650$), finding a $3.3\sigma$ preference ($\Delta {\chi }^2=-16.2$ for 3 additional degrees of freedom) for EDE over $\Lambda$CDM. The EDE contributes a maximum fractional energy density of $f_{\mathrm{EDE}}(z_c)=0.163_{-0.04}^{+0.047}$ at a redshift $z_c=3357\pm 200$ and leads to a CMB inferred value of the Hubble constant $H_0=74.2_{-2.1}^{+1.9}$ km/s/Mpc. We find that Planck and ACT DR4 data provide the majority of the improvement in ${\chi }^2$, and that the inclusion of SPT-3G pulls the posterior of $f_{\mathrm{EDE}}(z_c)$ away from $\Lambda$CDM. This is the first time that a moderate preference for EDE has been reported for these three combined CMB data sets. We find that including measurements of supernovae luminosity distances and the baryon acoustic oscillation standard ruler only minimally affects the preference ($3.0\sigma$), while measurements that probe the clustering of matter at late times - the lensing potential power spectrum from Planck and $f{\sigma }_8$ from BOSS - decrease the significance of the preference to 2.6$\sigma$. Conversely, adding a prior on the $H_0$ value as reported by the SH0ES collaboration increases the preference to the $4-5\sigma$ level. In the absence of this prior, the inclusion of Planck TT data at $\ell >1300$ reduces the preference from $3.0\sigma$ to $2.3\sigma$ and the constraint on $f_{\mathrm{EDE}}(z_c)$ becomes compatible with $\Lambda$CDM at $1\sigma$. We explore whether systematic errors in the Planck polarization data may affect our conclusions and find that changing the TE polarization efficiencies significantly reduces the Planck preference for EDE. More work will be necessary to establish whether these hints for EDE within CMB data alone are the sole results of systematic errors or an opening to new physics.

    ↳ astro-ph.COhep-phPRD(2022)·126 citations

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