Wed·Sep 16, 2020Wednesday·September 16, 2020

1. 01*

   Constraints on neutrino non-standard interactions from LHC data with large missing transverse momentum

   DianYu Liu🇨🇳 · ChuanLe Sun🇨🇳 · Jun Gao🇨🇳

   The possible non-standard interactions (NSIs) of neutrinos with matter plays important role in the global determination of neutrino properties. In our study we select various data sets from LHC measurements at 13 TeV with integrated luminosities of $35\sim 139$ fb${}^{-1}$, including production of a single jet, photon, $W/Z$ boson, or charged lepton accompanied with large missing transverse momentum. We derive constraints on neutral-current NSIs with quarks imposed by different data sets in a framework of either effective operators or simplified $Z^{\prime }$ models. We use theoretical predictions of productions induced by NSIs at next-to-leading order in QCD matched with parton showering which stabilize the theory predictions and result in more robust constraints. In a simplified $Z^{\prime }$ model we obtain a 95% CLs upper limit on the conventional NSI strength $ϵ$ of 0.042 and 0.0028 for a $Z^{\prime }$ mass of 0.2 and 2 TeV respectively. We also discuss possible improvements from future runs of LHC with higher luminosities.

   hep-phhep-exJHEP(2021)·19 citations
2. 02*

   Gauge-invariant description of the Higgs resonance and its phenomenological implications

   Axel Maas🇦🇹 · René Sondenheimer🇦🇹

   We investigate the phenomenological consequences of a strict gauge-invariant formulation of the Higgs particle. This requires a description of the observable scalar particle in terms of a bound state structure. Although this seems to be at odds with the common treatment of electroweak particle physics at first glance, the properties of the bound state can be described in a perturbative fashion due to the Fröhlich-Morchio-Strocchi (FMS) framework. In particular a relation between the bound-state Higgs and the elementary Higgs field is obtained within $R_{\xi }$ gauges such that the main quantitative properties of the conventional description reappear in leading order of the FMS expansion. Going beyond leading order, we show that the pole structure of the elementary and the bound-state propagator coincide to all orders in a perturbative expansion. However, slight deviations of scattering amplitudes containing off-shell Higgs contributions can be caused by the internal bound state structure. We perform a consistent perturbative treatment to all orders in the FMS expansion to quantify such deviations and demonstrate how gauge-invariant expressions arrange in a natural way at the one-loop level. This also provides a gauge-invariant Higgs spectral function which is not plagued by positivity violations or unphysical thresholds. Furthermore, the mass extracted from the gauge-invariant bound state is only logarithmically sensitive to the scale of new physics at one-loop order in contrast to its elementary counterpart.

   hep-phhep-exhep-latPRD(2020)·37 citations
3. 03*

   Benchmarking Machine Learning Techniques with Di-Higgs Production at the LHC

   Benjamin Tannenwald (1)🇺🇸 · Christopher Neu (1)🇺🇸 · Ang Li (1)🇺🇸 · Gracemarie Buehlmann (1)🇺🇸 · Anna Cuddeback (1)🇺🇸 · Leigh Hatfield (1)🇺🇸 · Ruhi Parvatam (1)🇺🇸 · Colby Thompson (1) ((1) University of Virginia)🇺🇸

   Many domains of high energy physics analysis are starting to explore machine learning techniques. Powerful methods can be used to identify and measure rare processes from previously insurmountable backgrounds. One of the most profound Standard Model signatures still to be discovered at the LHC is the pair production of Higgs bosons through the Higgs self-coupling. The small cross section of this process makes detection very difficult even for the decay channel with the largest branching fraction ($hh\to b\bar{b}b\bar{b}$). This paper benchmarks a variety of approaches (boosted decision trees, various neural network architectures, semi-supervised algorithms) against one another to catalog a few of the various techniques available to high energy physicists as the era of the HL-LHC approaches.

   hep-phhep-ex13 citations
4. 04*

   Factorization at Subleading Power and Endpoint Divergences in $h\to \gamma \gamma$ Decay: II. Renormalization and Scale Evolution

   Ze Long Liu🇺🇸 · Bianka Mecaj🇩🇪 · Matthias Neubert🇩🇪 · Xing Wang🇩🇪

   Building on the recent derivation of a bare factorization theorem for the $b$-quark induced contribution to the $h\to \gamma \gamma$ decay amplitude based on soft-collinear effective theory, we derive the first renormalized factorization theorem for a process described at subleading power in scale ratios, where $\lambda =m_b/M_h\ll 1$ in our case. We prove two refactorization conditions for a matching coefficient and an operator matrix element in the endpoint region, where they exhibit singularities giving rise to divergent convolution integrals. The refactorization conditions ensure that the dependence of the decay amplitude on the rapidity regulator, which regularizes the endpoint singularities, cancels out to all orders of perturbation theory. We establish the renormalized form of the factorization formula, proving that extra contributions arising from the fact that "endpoint regularization" does not commute with renormalization can be absorbed, to all orders, by a redefinition of one of the matching coefficients. We derive the renormalization-group evolution equation satisfied by all quantities in the factorization formula and use them to predict the large logarithms of order $\alpha {\alpha }_s^2{L}^k$ in the three-loop decay amplitude, where $L=\ln (-M_h^2/m_b^2)$ and $k=6,5,4,3$. We find perfect agreement with existing numerical results for the amplitude and analytical results for the three-loop contributions involving a massless quark loop. On the other hand, we disagree with the results of previous attempts to predict the series of subleading logarithms $\sim \alpha {\alpha }_s^n{L}^{2n+1}$.

   hep-phhep-thJHEP(2021)·81 citations
5. 05*

   Diquark Induced Short-Range Nucleon-Nucleon Correlations \& the EMC Effect

   Jennifer Rittenhouse West🇺🇸

   Diquark formation across a short-range nucleon-nucleon pair is proposed as the underlying QCD physics of short-range correlations (SRC) in nuclei. SRC pairs have been proposed as the cause of distorted quark behavior in nuclei; experimentally observed quark momentum distribution distortions termed the EMC effect. The strong spatial overlap of SRC pairs brings nucleon constituents within range of inter-nucleon QCD potentials and any bonds formed - such as the diquark bond - affects their distributions. In this SRC model, diquarks form in the $3_{\mathrm{C}}\otimes 3_{\mathrm{C}}\to {\bar{3}}_{\mathrm{C}}$ channel of $\mathrm{SU}(3{)}_{\mathrm{C}}$ acting on valence quarks from highly overlapping nucleon wavefunctions. The most energetically favorable diquark is a valence $u$ quark from one nucleon with a valence $d$ quark from the other in a spin-0 state bound together via continual single gluon exchange and an attractive quantum chromodynamics short-range potential. Formation of a new scalar isospin-singlet $[ud]$ diquark across a NN pair is proposed as the primary QCD-level theoretical foundation for SRC models of distorted structure functions in $\mathrm{A}\ge 3$ nuclei. Contributions from the higher mass spin-1 isospin triplet states $(ud)$, $(uu)$ and $(dd)$ are possible, with the spin-1 $(ud)$ diquark proposed as a higher mass but viable structure function distortion mechanism for the spin-1 ground state deuteron. Predictions are made for lepton scattering experiments on ${}^3\mathrm{H}$ and ${}^3\mathrm{He}$ nuclear targets, with implications for the coefficients of the 3-valence quark Fock states in the nucleon wavefunction.

   hep-phastro-ph.HEnucl-thNPA(2023)·19 citations
6. 06*

   $N=1$ trinification from dimensional reduction of $N=1$, $10D$ $E_8$ over $SU(3)/U(1)\times U(1)\times Z_3$ and its phenomenological consequences

   George Manolakos🇬🇷 · Gregory Patellis🇬🇷 · George Zoupanos🇬🇷

   We present an extension of the Standard Model that results from the dimensional reduction of the $\mathcal{N}=1$, $10D$ $E_8$ group over a $M_4\times B_0/{\mathbf{Z}}_3$ space, where $B_0$ is the nearly-Kähler manifold $SU(3)/U(1)\times U(1)$ and ${\mathbf{Z}}_3$ is a freely acting discrete group on $B_0$. Using the Wilson flux breaking mechanism we are left in four dimensions with an $\mathcal{N}=1$ $SU(3{)}^3$ gauge theory. Below the unification scale we have a two Higgs doublet model in a split-like supersymmetric version of the Standard Model, which yields third generation quark and light Higgs masses within the experimental limits and predicts the LSP $\sim$ 1500 $GeV$.

   hep-phhep-thPLB(2021)·25 citations
7. 07*

   Heavy Quarkonium at finite temperature and chemical potential

   Stefano Carignano🇪🇸 · Joan Soto🇪🇸

   We generalize known results for heavy quarkonium in a thermal bath to the case of a finite baryonic density, and provide a number of formulas for the energy shift and decay width that hold at weak coupling for sufficiently large temperature and/or chemical potential. We find that a non-vanishing decay width requires a temperature larger than the typical binding energy, no matter how large the chemical potential is. This implies that at zero temperature the dissociation mechanism of heavy quarkonium is due entirely to screening, unlike in the finite temperature case. We use several effective theories in order to sort out the contributions of the relevant energy and momentum scales. In particular, we consider contributions of the so called quasi-static magnetic modes. The generalization to the case of a finite isospin/strangeness chemical potential is trivial. We discuss possible applications to the SIS and NICA conditions, and compare with available lattice results.

   hep-phPRD(2020)·1 citation
8. 08*

   Nucleon resonances with higher spins in soft-wall AdS/QCD

   Valery E. Lyubovitskij🇩🇪 · Ivan Schmidt🇨🇱

   We present a study of electroexcitation of nucleon resonances with higher spins, in a soft-wall AdS/QCD model, comparing our results with existing data from the CLAS Collaboration at JLab, from MAMI, and other experiments.

   hep-phPRD(2020)·23 citations
9. 09*

   Revisiting the rare $H\to q_i{q}_j$ decays in the Standard Model

   J. I. Aranda🇲🇽 · G. González-Estrada🇲🇽 · J. Montaño🇲🇽 · F. Ramírez-Zavaleta🇲🇽 · E. S. Tututi🇲🇽

   We revisit the rare decays of the Higgs boson to two different quarks in the Standard Model, which arise at the one-loop level. We perform Taylor series expansions to the complete form factors of the decay amplitudes, according to their different mass hierarchies, this allow us to take full advantage of the GIM mechanism to eliminate spurious contributions and retain those that truly contribute. We found that Br$(H\to uc)$=$5.00\times 10^{-20}$, Br$(H\to ds)$=$1.19\times 10^{-11}$, Br$(H\to db)$=$5.16\times 10^{-9}$ and Br$(H\to sb)$=$1.15\times 10^{-7}$. Our predictions for the $H\to uc,ds$ decays disagree with previous results in the literature.

   hep-phJ.Phys.G(2020)·15 citations
10. 10*

    The transverse polarization of $\Lambda$ hyperons in $e^{+}{e}^{-}\to {\Lambda }^{\uparrow }hX$ processes within TMD factorization

    Hui Li🇨🇳 · Xiaoyu Wang🇨🇳 · Yongliang Yang🇨🇳 · Zhun Lu🇨🇳

    We investigate the transverse polarization of the $\Lambda$ hyperon in the processes $e^{+}{e}^{-}\to {\Lambda }^{\uparrow }{\pi }^{\pm }X$ and $e^{+}{e}^{-}\to {\Lambda }^{\uparrow }{K}^{\pm }X$ within the framework of the transverse momentum dependent~(TMD) factorization. The transverse polarization is contributed by the convolution of the transversely polarizing fragmentation function~(PFF) $D_{1T}^{\perp }$ of the lambda hyperon and the unpolarized fragmentation function $D_1$ of pion/kaon. We adopt the spectator diquark model result for $D_{1T}^{\perp }$ to numerically estimate the transverse polarization in $e^{+}{e}^{-}\to {\Lambda }^{\uparrow }hX$ process at the kinematical region of Belle Collaboration. To implement the TMD evolution formalism of the fragmentation functions, we apply two different parametrizations on the nonperturbative Sudakov form factors associated with the fragmentation functions of the $\Lambda$, pion and kaon. It is found that our prediction on the polarization in the $\Lambda {\pi }^{+}$ production and $\bar{\Lambda }{\pi }^{-}$ is consistent with the recent Belle measurement in size and sign, while the model predictions on the polarizations in $\Lambda {\pi }^{-}$ and $\Lambda K^{\pm }$ productions show strong disagreement with the Belle data. The reason for the discrepancies is discussed and possible approaches to improve the calculation in the future are also discussed.

    hep-phEPJC(2021)·16 citations
11. 11*

    Towards the finite quantum field theory

    Vladimir Sauli🇨🇿

    In this study, we propose a novel regularization/renormalization scheme that utilizes an auxiliary Feynman parameterization. This approach is employed to align a specified loop diagram with a designated unit of the form $1=\lambda /\lambda$. Within the proposed regularization technique, we formulate the standard renormalization scheme and demonstrate conditions under which it yields symmetry preserving results. It is demonstrated that its minimal form yields renormalized diagrams that are equivalent to those of the dimensional renormalization scheme, with the exception of their counterterms. Furthermore, a novel procedure for taking the soft limit $\lambda \to 0$, where a properly defined order of computational actions provides the field theory completely finite, is presented.The qualitative and quantitative distinctions between this approach and the standard scheme are highlighted. Both schemes are elucidated in the scalar model in 3+1D for pedagogical reasons. Subsequently, the proposed schemes are applied to the Standard Model at one loop level, e.g. we calculate photon and gluon polarizations. QCD effective charge is calculated in the finite QCD, exhibiting a clear evidence that the finite QCD is not ruled out but supported by experiment. In the final section, we offer a concise discussion on the softening of anomalies and the treatment of overlapping divergences, accompanied by illustrative examples.

    hep-phhep-th1 citation
12. 12*

    Ultralight Bosonic Field Mass Bounds from Astrophysical Black Hole Spin

    Matthew J. Stott🇬🇧

    Black Hole measurements have grown significantly in the new age of gravitation wave astronomy from LIGO observations of binary black hole mergers. As yet unobserved massive ultralight bosonic fields represent one of the most exciting features of Standard Model extensions, capable of providing solutions to numerous paradigmatic issues in particle physics and cosmology. In this work we explore bounds from spinning astrophysical black holes and their angular momentum energy transfer to bosonic condensates which can form surrounding the black hole via superradiant instabilities. Using recent analytical results we perform a simplified analysis with a generous ensemble of black hole parameter measurements where we find superradiance very generally excludes bosonic fields in the mass ranges; spin-0: $\{3.8\times 10^{-14}\mathrm{eV}\le {\mu }_0\le 3.4\times 10^{-11}\mathrm{eV},5.5\times 10^{-20}\mathrm{eV}\le {\mu }_0\le 1.3\times 10^{-16}\mathrm{eV},2.5\times 10^{-21}\mathrm{eV}\le {\mu }_0\le 1.2\times 10^{-20}\mathrm{eV}\}$, spin-1: $\{6.2\times 10^{-15}\mathrm{eV}\le {\mu }_1\le 3.9\times 10^{-11}\mathrm{eV},2.8\times 10^{-22}\mathrm{eV}\le {\mu }_1\le 1.9\times 10^{-16}\mathrm{eV}\}$ and spin-2: $\{2.2\times 10^{-14}\mathrm{eV}\le {\mu }_2\le 2.8\times 10^{-11}\mathrm{eV},1.8\times 10^{-20}\mathrm{eV}\le {\mu }_2\le 1.8\times 10^{-16}\mathrm{eV},6.4\times 10^{-22}\mathrm{eV}\le {\mu }_2\le 7.7\times 10^{-21}\mathrm{eV}\}$ respectively. We also explore these bounds in the context of specific phenomenological models, specifically the QCD axion, M-theory models and fuzzy dark matter sitting at the edges of current limits. In particular we include recent measurements of event GW190521 and M87* used to constrain both the masses and decay constants of axion like fields. Finally we comment a simple example of a spectrum of fields for the spin-0 and spin-1 cases.

    hep-phgr-qchep-th95 citations
13. 13*

    Analytic results for scalar-mediated Higgs boson production in association with two jets

    Lucy Budge🇬🇧 · John M. Campbell🇺🇸 · R. Keith Ellis🇬🇧 · Satyajit Seth🇮🇳

    We present compact analytic formulae for all one-loop amplitudes representing the production of a Higgs boson in association with two jets, mediated by a colour triplet scalar particle. Many of the integral coefficients present for scalar mediators are identical to the case when a massive fermion circulates in the loop, reflecting a close relationship between the two theories. The calculation is used to study Higgs boson production in association with two jets in a simplified supersymmetry (SUSY) scenario in which the dominant additional contributions arise from loops of top squarks. The results presented here facilitate an indirect search for top squarks in this channel, by a precision measurement of the corresponding cross-section. However, we find that the potential for improved discrimination between the SM and SUSY cases suggested by the pattern of results in the 1- and 2-jet samples is unlikely to be realized due to the loss in statistical power compared to an inclusive analysis.

    hep-phJ.Phys.G(2021)·1 citation
14. 14*

    SMEFT ATLAS of $\Delta F=2$ Transitions

    Jason Aebischer🇺🇸 · Christoph Bobeth🇩🇪 · Andrzej J. Buras🇩🇪 · Jacky Kumar🇨🇦

    We present a model-independent anatomy of the $\Delta F=2$ transitions $K^0-{\bar{K}}^0$, $B_{s,d}-{\bar{B}}_{s,d}$ and $D^0-{\bar{D}}^0$ in the context of the Standard Model Effective Field Theory (SMEFT). We present two master formulae for the mixing amplitude $[M_{12}{]}_{\text{BSM}}$. One in terms of the Wilson coefficients (WCs) of the Low-Energy Effective Theory (LEFT) operators evaluated at the electroweak scale ${\mu }_{\text{ew}}$ and one in terms of the WCs of the SMEFT operators evaluated at the BSM scale $\Lambda$. The coefficients $P_a^{ij}$ entering these formulae contain all the information below the scales ${\mu }_{\text{ew}}$ and $\Lambda$, respectively. Renormalization group effects from the top-quark Yukawa coupling play the most important role. The collection of the individual contributions of the SMEFT operators to $[M_{12}{]}_{\text{BSM}}$ can be considered as the SMEFT ATLAS of $\Delta F=2$ transitions and constitutes a travel guide to such transitions far beyond the scales explored by the LHC. We emphasize that this ATLAS depends on whether the down-basis or the up-basis for SMEFT operators is considered. We illustrate this technology with tree-level exchanges of heavy gauge bosons ($Z^{\prime }$, $G^{\prime }$) and corresponding heavy scalars.

    hep-phhep-exhep-latJHEP(2020)·78 citations
15. 15*

    Baryogenesis from the weak scale to the grand unification scale

    Dietrich Bodeker🇩🇪 · Wilfried Buchmuller🇩🇪

    We review the current status of baryogenesis with emphasis on electroweak baryogenesis and leptogenesis. The first detailed studies were carried out for SU(5) GUT models where CP-violating decays of leptoquarks generate a baryon asymmetry. These GUT models were excluded by the discovery of B+L violating sphaleron processes at high temperatures. Yet a new possibility emerged, electroweak baryogenesis. Here sphaleron processes generate a baryon asymmetry during a strongly first-order phase transition. This mechanism has been studied in many extensions of the Standard Model. However, constraints from the LHC and from low-energy precision experiments exclude most of the known models, leaving composite Higgs models of electroweak symmetry breaking as an interesting possibility. Sphaleron processes are also the basis of leptogenesis, where CP-violating decays of heavy right-handed neutrinos generate a lepton asymmetry which is partially converted to a baryon asymmetry. This mechanism is closely related to the one of GUT baryogenesis, and simple estimates based on GUT models can explain the order of magnitude of the observed baryon-to-photon ratio. In the one-flavour approximation an upper bound on the light neutrino masses has been derived which is consistent with the cosmological upper bound on the sum of neutrino masses. For quasi-degenerate right-handed neutrinos the leptogenesis temperature can be lowered from the GUT scale down to the weak scale, and CP-violating oscillations of GeV sterile neutinos can also lead to successfull leptogenesis. Significant progress has been made in developing a full field theoretical description of thermal leptogenesis, which demonstrated that interactions with gauge bosons of the thermal plasma play a crucial role. Finally, we discuss recent ideas how the seesaw mechanism and B-L breaking at the GUT scale can be probed by gravitational waves.

    hep-phastro-ph.COhep-thRMP(2021)·276 citations
16. 16*

    Image segmentation for analyzing galaxy-galaxy strong lensing systems

    Bryan Ostdiek🇺🇸 · Ana Diaz Rivero🇺🇸 · Cora Dvorkin🇺🇸

    The goal of this paper is to develop a machine learning model to analyze the main gravitational lens and detect dark substructure (subhalos) within simulated images of strongly lensed galaxies. Using the technique of image segmentation, we turn the task of identifying subhalos into a classification problem, where we label each pixel in an image as coming from the main lens, a subhalo within a binned mass range, or neither. Our network is only trained on images with a single smooth lens and either zero or one subhalo near the Einstein ring. On an independent test set with lenses with large ellipticities, quadrupole and octopole moments, and for source apparent magnitudes between 17-25, the area of the main lens is recovered accurately. On average, only 1.3% of the true area is missed and 1.2% of the true area is added to another part of the lens. In addition, subhalos as light as $10^{8.5}{M}_{\odot }$ can be detected if they lie in bright pixels along the Einstein ring. Furthermore, the model is able to generalize to new contexts it has not been trained on, such as locating multiple subhalos with varying masses or more than one large smooth lens.

    ↳ astro-ph.COastro-ph.IMhep-phphysics.data-anAstron.Astrophys.(2022)·31 citations
17. 17*

    A machine learning approach for efficient multi-dimensional integration

    Boram Yoon🇺🇸

    We propose a novel multi-dimensional integration algorithm using a machine learning (ML) technique. After training a ML regression model to mimic a target integrand, the regression model is used to evaluate an approximation of the integral. Then, the difference between the approximation and the true answer is calculated to correct the bias in the approximation of the integral induced by a ML prediction error. Because of the bias correction, the final estimate of the integral is unbiased and has a statistically correct error estimation. The performance of the proposed algorithm is demonstrated on six different types of integrands at various dimensions and integrand difficulties. The results show that, for the same total number of integrand evaluations, the new algorithm provides integral estimates with more than an order of magnitude smaller uncertainties than those of the VEGAS algorithm in most of the test cases.

    ↳ physics.comp-phcs.LGhep-phSci.Rep.(2021)·2 citations
18. 18*

    Pulsar tests of the graviton mass

    Lijing Shao🇨🇳

    In Einstein's general relativity (GR), gravity is described by a massless spin-2 metric field, and the extension of GR to include a mass term for the graviton has profound implication for gravitation and cosmology. Besides the gravity experiments carried out in the Solar System and those recently with gravitational waves (GWs), pulsar timing observations provide a complementary means to test the masslessness of graviton. In this contribution, I overview three methods in probing the mass of graviton from precision timing of binary pulsars via the modified gravitational radiation (hence, the observed damping rate of the orbital period), as well as from the pulsar-timing-array (PTA) experiments via the modified Hellings-Downs angular-correlation curve. These tests probe different aspects of gravitation in its kinematics and dynamics, complementing tests of other kinds and providing valuable information to the fundamental theory of gravity.

    ↳ gr-qcastro-ph.HEhep-phAstron.Nachr.(2021)·4 citations
19. 19*

    Beam Energy dependence of Light Nuclei Production in Au+Au Collisions

    Wenbin Zhao🇨🇳 · Chun Shen🇺🇸 · Che Ming Ko🇺🇸 · Quansheng Liu🇨🇳 · Huichao Song🇨🇳

    We study the collision energy dependence of (anti-)deuteron and (anti-)triton production in the most central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=$ 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV, using the nucleon coalescence model. The needed phase-space distribution of nucleons at the kinetic freeze-out is generated from a new 3D hybrid dynamical model (\texttt{iEBE-MUSIC}) by using a smooth crossover equation of state (EoS) without a QCD critical point. Our model calculations predict that the coalescence parameters of (anti-)deuteron ($B_2(d)$ and $B_2(\bar{d})$) decrease monotonically as the collision energy increases, and the light nuclei yield ratio $N_t{N}_p/N_d^2$ remains approximately a constant with respect to the collision energy. These calculated observables fail to reproduce the non-monotonic behavior of the corresponding data from the STAR Collaboration. Without including any effects of the critical point in our model, our results serve as the baseline predictions for the yields of light nuclei in the search for the possible QCD critical points from the experimental beam energy scan of heavy ion collisions.

    ↳ nucl-thhep-phnucl-exPRC(2020)·47 citations
20. 20*

    Direct CP violation in beauty and charm hadron decays

    Ignacio Bediaga🇧🇷 · Carla Göbel🇧🇷

    Since the discovery of CP violation more than 5 decades ago, this phenomenon is still attracting a lot of interest. Among the many fascinating aspects of this subject, this review is dedicated to direct CP violation in non-leptonic decays. The advances within the last decade have been enormous, driven by the increasingly large samples of b- and c-hadron decays, and have led to very interesting results such as large CP asymmetries in charmless B decays and the observation of direct CP violation in the charm sector. We address the quest for understanding the origin of strong phases, the importance of final state interactions and the relation with CPT symmetry, and different approaches to measure direct CP violation in these decays. The main experimental results and their implications are then discussed.

    ↳ hep-exhep-phPPNP(2020)·46 citations
21. 21*

    Unified Interacting Quark Matter and its Astrophysical Implications

    Chen Zhang🇨🇦 · Robert B. Mann🇨🇦

    We investigate interacting quark matter (IQM), including the perturbative QCD correction and color superconductivity, for both up-down quark matter ($ud$QM) and strange quark matter (SQM). We first derive an equation of state (EOS) unifying all cases by a simple reparametrization and rescaling, through which we manage to maximally reduce the number of degrees of freedom. We find, in contrast to the conventional EOS $p=1/3(\rho -4B_{\mathrm{eff}})$ for non-interacting quark matter, that taking the extreme strongly interacting limit on the unified IQM EOS gives $p=\rho -2B_{\mathrm{eff}}$, where $B_{\mathrm{eff}}$ is the effective bag constant. We employ the unified EOS to explore the properties of pure interacting quark stars (IQSs) composed of IQM. We describe how recent astrophysical observations, such as the pulsar-mass measurements, the NICER analysis, and the binary merger gravitational-wave events GW170817, GW190425, and GW190814, further constrain the parameter space. An upper bound for the maximum allowed mass of IQSs is found to be $M_{\mathrm{TOV}}\lesssim 3.23M_{\odot }$. Our analysis indicates a new possibility that the currently observed compact stars, including the recently reported GW190814's secondary component ($M=2.59_{-0.09}^{+0.08}{M}_{\odot }$), can be quark stars composed of interacting quark matter.

    ↳ astro-ph.HEgr-qchep-phnucl-thPRD(2021)·101 citations
22. 22*

    A Synthetic Macroscopic Magnetic Unipole

    Emmanouil Markoulakis🇬🇷 · John Chatzakis🇬🇷 · Anthony Konstantaras🇬🇷 · Emmanuel Antonidakis🇬🇷

    We demonstrate experimentally with a prototype for the first time, that an artificial emergent magnetic unipole hedgehog field in a simply connected three dimensional domain is possible, emulating effectively the Dirac model by simply using a novel permanent magnets' topology and geometrical arrangement in a ring array. Although similar effects were demonstrated by others over the last decade, with these effects usually observed and lasting for a small fraction in time and applied at the quantum or microscopic scale using primary BECs, Skyrmions, Spin Ice and recently Chiral Magnets this was never shown until now and performed at the macro scale and by using normal magnets. The synthetic magnetic unipole ring array prototype progressively twists and steers the magnetic flux into vanishing curl field (i.e. vortex) geometry towards the center of the ring and its air cap. This mere act alone proves enough to create the desired effect and an apparent isolated magnetic unipole region is observed at the center of this magnetic ring array, as we have mapped with a three axis magnetometer and show with the quantum magnetic-optic device flux viewer, the ferrolens. This magnetic unipole is stable at room temperature. Because its macroscopic nature we were able to record for the first time the unique signal signature patterns of magnetic monopoles synthetic or natural, passing through a non-ideal ohmic solenoid shown in Fig.17 which can be used by researches to aid them in the detection of magnetic monopoles.

    ↳ physics.ins-detcond-mat.str-elhep-exhep-phPhys.Scripta(2020)·3 citations
23. 23*

    Inclusive Electron Scattering And The GENIE Neutrino Event Generator

    A. Papadopoulou🇺🇸 · A. Ashkenazi🇺🇸 · S. Gardiner🇺🇸 · M. Betancourt🇺🇸 · S. Dytman🇺🇸 · L.B. Weinstein🇺🇸 · E. Piasetzky🇮🇱 · F. Hauenstein🇺🇸 · M. Khachatryan🇺🇸 · S. Dolan🇨🇭 · G. Megias🇯🇵 · O. Hen (The electrons for neutrinos collaboration)🇺🇸

    The extraction of neutrino mixing parameters from accelerator-based neutrino oscillation experiments relies on proper modeling of neutrino-nucleus scattering processes using neutrino-interaction event generators. Experimental tests of these generators are difficult due to the broad range of neutrino energies produced in accelerator-based beams and the low statistics of current experiments. Here we overcome these difficulties by exploiting the similarity of neutrino and electron interactions with nuclei to test neutrino event generators using high-precision inclusive electron scattering data. To this end, we revised the electron-scattering mode of the GENIE event generator ($e$-GENIE) to include electron-nucleus bremsstrahlung radiation effects and to use, when relevant, the exact same physics models and model parameters, as the standard neutrino-scattering version. We also implemented new models for quasielastic (QE) scattering and meson exchange currents (MEC) based on the theory-inspired SuSAv2 approach. Comparing the new $e$-GENIE predictions with inclusive electron scattering data, we find an overall adequate description of the data in the QE- and MEC-dominated lower energy transfer regime, especially when using the SuSAv2 models. Higher energy transfer-interactions, which are dominated by resonance production, are still not well modeled by $e$-GENIE.

    ↳ nucl-thhep-exhep-phnucl-exPRD(2021)·48 citations
24. 24*

    Criteria for projected discovery and exclusion sensitivities of counting experiments

    Prudhvi N. Bhattiprolu🇺🇸 · Stephen P. Martin🇺🇸 · James D. Wells🇺🇸

    The projected discovery and exclusion capabilities of particle physics and astrophysics/cosmology experiments are often quantified using the median expected $p$-value or its corresponding significance. We argue that this criterion leads to flawed results, which for example can counterintuitively project lessened sensitivities if the experiment takes more data or reduces its background. We discuss the merits of several alternatives to the median expected significance, both when the background is known and when it is subject to some uncertainty. We advocate for standard use of the "exact Asimov significance" $Z^{\mathrm{A}}$ detailed in this paper.

    ↳ physics.data-anhep-exhep-phEPJC(2021)·38 citations
25. 25*

    The tune of the universe: the role of plasma in tests of strong-field gravity

    Vitor Cardoso🇵🇹 · Wen-di Guo🇨🇳 · Caio F. B. Macedo🇧🇷 · Paolo Pani🇮🇹

    Gravitational-wave astronomy, together with precise pulsar timing and long baseline interferometry, is changing our ability to perform tests of fundamental physics with astrophysical observations. Some of these tests are based on electromagnetic probes or electrically charged bodies, and assume an empty universe. However, the cosmos is filled with plasma, a dilute medium which prevents the propagation of low-frequency, small-amplitude electromagnetic waves. We show that the plasma hinders our ability to perform some strong-field gravity tests, in particular: (i)~nonlinear plasma effects dramatically quench plasma-driven superradiant instabilities; (ii)~the contribution of electromagnetic emission to the inspiral of charged black hole binaries is strongly suppressed; (iii)~electromagnetic-driven secondary modes, although present in the spectrum of charged black holes, are excited to negligible amplitude in the gravitational-wave ringdown signal. The last two effects are relevant also in the case of massive fields that propagate in vacuum and can jeopardize tests of modified theories of gravity containing massive degrees of freedom.

    ↳ gr-qcastro-ph.HEhep-phhep-thMNRAS(2021)·64 citations
26. 26*

    An introduction to the time evolution of model universes

    Vinicius S. Aderaldo🇧🇷 · Victor P. Goncalves🇧🇷

    In this paper we describe the evolution of the Universe in terms of the Friedmann equation, which takes into account of the composition and geometry of the Universe. The dependence of the solution on the geometry and composition for different combinations of the basic constituents are discussed. The distinct behaviors for the temporal evolution of the Universe are determined and the scenario predicted by the Standard Cosmology is presented.

    ↳ physics.pop-phhep-phRev.Bras.Ens.Fis.(2020)·2 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.