Fri·Sep 4, 2015Friday·September 4, 2015

1. 01*

   Weakly-Interacting Massive Particles in Non-supersymmetric SO(10) Grand Unified Models

   Natsumi Nagata🇺🇸 · Keith A. Olive🇺🇸 · Jiaming Zheng🇺🇸

   Non-supersymmetric SO(10) grand unified theories provide a framework in which the stability of dark matter is explained while gauge coupling unification is realized. In this work, we systematically study this possibility by classifying weakly interacting DM candidates in terms of their quantum numbers of $\text{SU}(2{)}_L\otimes \text{U}(1{)}_Y$, $B-L$, and $\text{SU}(2{)}_R$. We consider both scalar and fermion candidates. We show that the requirement of a sufficiently high unification scale to ensure a proton lifetime compatible with experimental constraints plays a strong role in selecting viable candidates. Among the scalar candidates originating from either a 16 or 144 of SO(10), only SU(2)${}_L$ singlets with zero hypercharge or doublets with $Y=1/2$ satisfy all constraints for $\text{SU}(4{)}_C\otimes \text{SU}(2{)}_L\otimes \text{SU}(2{)}_R$ and $\text{SU}(3{)}_C\otimes \text{SU}(2{)}_L\otimes \text{SU}(2{)}_R\otimes \text{U}(1{)}_{B-L}$ intermediate scale gauge groups. Among fermion triplets with zero hypercharge, only a triplet in the 45 with intermediate group $\text{SU}(4{)}_C\otimes \text{SU}(2{)}_L\otimes \text{SU}(2{)}_R$ leads to solutions with $M_{\mathrm{GUT}}>M_{\mathrm{int}}$ and a long proton lifetime. We find three models with weak doublets and $Y=1/2$ as dark matter candidates for the $\text{SU}(4{)}_C\otimes \text{SU}(2{)}_L\otimes \text{SU}(2{)}_R$ and $\text{SU}(4{)}_C\otimes \text{SU}(2{)}_L\otimes \text{U}(1{)}_R$ intermediate scale gauge groups assuming a minimal Higgs content. We also discuss how these models may be tested at accelerators and in dark matter detection experiments.

   hep-phJHEP(2015)·69 citations
2. 02*

   QCD Dirac Spectrum at Finite Chemical Potential: Anomalous Effective Action, Berry Phase and Composite Fermions

   Yizhuang Liu🇺🇸 · Ismail Zahed🇺🇸

   We show that the QCD Dirac spectrum at finite chemical potential using a matrix model in the spontaneously broken phase, is amenable to a generic 2-dimensional effective action. The eigenvalues form a droplet with strong screening and plasmon oscillation. The droplet is threaded by a magnetic vortex which is at the origin of a Berry phase. For quarks in the complex or Dirac representation, the anomalous transport in the droplet of eigenvalues bear some similarities with that in droplets of composite fermions at half filling suggesting that the latters maybe Dirac fermions.

   hep-phcond-mat.str-el7 citations
3. 03*

   Natural Heavy Supersymmetry

   Brian Batell🇨🇭 · Gian F. Giudice🇨🇭 · Matthew McCullough🇨🇭

   We study how, as a result of the scanning of supersymmetry breaking during the cosmological evolution, a relaxation mechanism can naturally determine a hierarchy between the weak scale and the masses of supersymmetric particles. Supersymmetry breaking is determined by QCD instanton effects, in an extremely minimal setup in which a single field drives the relaxation and breaks supersymmetry. Since gauginos are lighter than the other supersymmetric particles by a one-loop factor, the theory is a realisation of Split Supersymmetry free from the naturalness problem.

   hep-phJHEP(2015)·96 citations
4. 04*

   Constraining Effective Self Interactions of Fermionic Dark Matter

   Kamakshya Prasad Modak🇮🇳

   The idea of Dark Matter (DM) with self interaction was invoked to resolve a number of discrepancies between the simulation based predictions by collisionless cold DM and the astrophysical observations on galactic and subgalactic scales. Evidences for self interaction would have striking implications for particle nature of DM. In order to reconcile such astrophysical observations for self interaction with particle properties for DM, we consider the general scenario of self interacting Dirac fermionic DM, $\chi$. Also since the exact particle physics model for DM is yet to be probed, we simply adopt the effective model independent framework for DM self interaction which occurs via the most general effective 4-fermion operators invariant under both Lorentz and CPT transformations. From the thorough investigation of the interrelations among the parameters in this framework, namely, the effective DM self couplings ($G_i$), DM mass ($m_{\chi }$) and relative velocity ($v_{\mathrm{rel}}$), it can be inferred that $G_i$ decrease with increasing $m_{\chi }$ for a given DM self interaction strength. Moreover, for few types of effective operators the values of $G_i$ fall off with increasing $v_{\mathrm{rel}}$ while they remain roughly constant for a wide range of $v_{\mathrm{rel}}$ for other cases. In addition, the parameter space in this framework is constrained by the claimed observational results of $\frac{\sigma }{m_{\chi }}$ on cluster scales (Abell 3827, Bullet Cluster) after averaging the DM self interaction cross sections over DM velocity distribution in the cluster. This puts interesting constraints on the values of effective DM self couplings for different fermionic DM masses for various effective operators (scalar, vector, etc.) of DM self interactions in this scenario. Some other implications of DM effective self interaction are also discussed in this model independent framework.

   hep-phastro-ph.COastro-ph.GAastro-ph.HE4 citations
5. 05*

   Finite Volume Cumulant Expansion in QCD-Colorless Plasma

   M. Ladrem🇸🇦 · M.A.A. Ahmed🇸🇦 · Z. Al-Full🇸🇦 · S. Cherif🇩🇿

   Due to the finite size effects, the localisation of the phase transition in finite systems and the determination of its order, become an extremely difficult task, even in the simplest known cases. In order to identify and locate the finite volume transition point $T_0(V)$ of the QCD deconfinement phase transition to a Colorless QGP, we have developed a new approach using the finite size cumulant expansion of the order parameter and the $L_{mn}$-method. The first six cumulants $C_{1,2,3,4,5,6}$ with the corresponding under-normalized ratios(skewness $\Sigma$, kurtosis $\kappa$ ,pentosis ${\Pi }_{\pm }$ and hexosis ${\mathcal{H}}_{1,2,3}$) and three unnormalized combinations of them ($\mathcal{O}={\sigma }^2\kappa {\mathbf{\Sigma }}^{-1}$, $\mathcal{U}={\sigma }^{-2}{\mathbf{\Sigma }}^{-1}$, $\mathcal{N}={\sigma }^2\kappa$) are calculated and studied as functions of $(T,V)$. A new approach, unifying in a clear and consistent way the definitions of cumulant ratios, is proposed. A numerical FSS analysis of the obtained results has allowed us to locate accurately the finite volume transition point. The extracted transition temperature value $T_0(V)$ agrees with that expected $T_0^N(V)$ from the order parameter and the thermal susceptibility ${\chi }_T\left(T,V\right)$, according to the standard procedure of localization to within about $2\%$. In addition to this, a very good correlation factor is obtained proving the validity of our cumulants method. The agreement of our results with those obtained by means of other models is remarkable.

   hep-phEPJC(2015)·8 citations
6. 06*

   Hyperon forward spin polarizability gamma0 in baryon chiral perturbation theory

   Astrid Hiller Blin🇪🇸 · Thomas Gutsche🇩🇪 · Tim Ledwig🇪🇸 · Valery E. Lyubovitskij🇩🇪

   We present the calculation of the hyperon forward spin polarizability gamma0 using manifestly Lorentz covariant baryon chiral perturbation theory including the intermediate contribution of the spin 3/2 states. As at the considered order the extraction of gamma0 is a pure prediction of chiral perturbation theory, the obtained values are a good test for this theory. After including explicitly the decuplet states, our SU(2) results have a very good agreement with the experimental data and we extend our framework to SU(3) to give predictions to the hyperons' gamma0 values. Prominent are the Sigma^- and Xi^- baryons as their photon transition to the decuplet is forbidden in SU(3) symmetry and therefore they are not sensitive to the explicit inclusion of the decuplet in the theory.

   hep-phPRD(2015)·17 citations
7. 07*

   Constraints on the Jet-Medium Coupling from Measurements at RHIC and LHC

   Barbara Betz🇩🇪 · Florian Senzel🇩🇪 · Carsten Greiner🇩🇪 · Miklos Gyulassy🇺🇸

   The measured data on the nuclear modification factor for pions and reconstructed jets as well as on the high-pT elliptic flow at RHIC and LHC energies are compared to results from a linear pQCD and a highly non-linear hybrid AdS holographic model of jet-energy loss. We find that the high-pT ellitic flow requires to include realistic medium transverse flow fields and a jet-medium coupling including the effects of the energy of the jet, the temperature of the bulk medium, and non-equilibrium effects close to the phase transition. We extend our jet-energy loss model that is coupled to state-of-the-art hydrodynamic prescriptions to backgrounds generated by the parton cascade BAMPS. We demonstrate that the results for the hydrodynamic and the parton-cascade backgrounds show a remarkable similarity. Unfortunately, the results for both the pion and a parton-jet nuclear modification factor are insensitive to the jet-path dependence of the models considered.

   hep-phNucl.Part.Phys.Proc.(2016)·1 citation
8. 08*

   Enhanced Charged Higgs Production through W-Higgs Fusion in W-b Scattering

   Abdesslam Arhrib🇲🇦 · Kingman Cheung🇹🇼 · Jae Sik Lee🇰🇷 · Chih-Ting Lu🇹🇼

   We study the associated production of a charged Higgs boson with a bottom quark and a light quark at the LHC via p p \to H^\pm\,b\,j in the Two Higgs Doublet Models (2HDMs). Using the effective W approximation, we show that there is exact cancellation among various Feynman diagrams in high energy limit. This may imply that the production of charged Higgs can be significantly enhanced in the presence of large mass differences among the neutral Higgs bosons via W^\pm-Higgs fusion in the p p \to H^\pm\,b\,j process. Particularly, we emphasize the potential enhancement due to a light pseudoscalar boson $A$, which is still allowed by the current data by which we explicitly calculate the allowed regions in (M_A,\,\tan\beta) plane, and show that the production cross section can be as large as 0.1 pb for large $\tan \beta$. We also show that the transverse momentum distribution of the b quark can potentially distinguish the W^\pm-A fusion diagram from the top diagram. Finally, we point out further enhancement when we go beyond the 2HDMs.

   hep-phJHEP(2016)·13 citations
9. 09*

   Azimuthal distributions in radiative decay of polarized $\tau$ lepton

   G.I. Gakh🇺🇦 · M.I. Konchatnij🇺🇦 · N.P. Merenkov🇺🇦

   Various distributions over the angles of the emitted photon, especially over the azimuthal angle, in the one-meson radiative decay of the polarized $\tau$ lepton, ${\tau }^{-}\to {\pi }^{-}\gamma {\nu }_{\tau }$, have been investigated. In connection with this, the photon phase space is discussed in more detail since in the case of the polarized $\tau$ lepton it is not trivial. The decay matrix element contains both the inner bremsstrahlung and the resonance (structural) contributions. The azimuthal dependence of some observables have been calculated. They are the asymmetry of the differential decay width caused by the $\tau$ lepton polarization, the Stokes parameters of the emitted photon itself and the correlation parameters describing the influence of $\tau$-lepton polarization on the photon Stokes parameters. The numerical estimation was done in the $\tau$ lepton rest frame for arbitrary direction of the $\tau$ lepton polarization 3-vector. The vector and axial-vector form factors describing the structure-dependent part of the decay amplitude are determined using the chiral effective theory with resonances (R$\chi$T). It was found that the features of the azimuthal distributions allows to separate various terms in the spin-dependent contribution. The so-called up-down and right-left asymmetries are also calculated.

   hep-phZh.Eksp.Teor.Fiz.(2016)·1 citation
10. 10*

    Hydrogen recombination in the early Universe in the presence of a magnetic field

    N.O. Agasian🇷🇺 · S.M. Fedorov🇷🇺

    Hydrogen recombination in the early Universe in the presence of a magnetic field is studied. An equation for the temperature of recombination in the presence of a magnetic field is derived. Limiting cases of weak and strong fields are considered. It is demonstrated that there exists a critical magnetic field, above which the system stays in the phase of atomic hydrogen for all temperatures. The relative shift of the temperature of recombination in the presence of a magnetic field is estimated and it is demonstrated that this shift is small.

    hep-phastro-ph.COPhys.Atom.Nucl.(2016)·0 citations
11. 11*

    Looking through the Pseudo-Scalar Portal into Dark Matter: Novel Mono-Higgs and Mono-$Z$ Signatures at LHC

    Jose Miguel No🇬🇧

    Mono-$X$ signatures are a powerful collider probe of the nature of dark matter. We show that mono-Higgs and mono-$Z$ may be key signatures of pseudo-scalar portal interactions between dark matter and the SM. We demonstrate this using a simple renormalizable version of the portal, with a Two-Higgs-Doublet-Model as electroweak symmetry breaking sector. Mono-$Z$ and mono-Higgs signatures in this scenario are of resonant type, which constitutes a novel type of dark matter signature at LHC.

    hep-phhep-exPRD(2016)·114 citations
12. 12*

    Jet Quenching and Gluon to Hadron Fragmentation Function in Non-Equilibrium QCD at RHIC and LHC

    Gouranga C. Nayak🇺🇸

    Theoretical understanding of the observed jet quenching measurements at RHIC and LHC is challenging in QCD because it requires understanding of parton to hadron fragmentation function in non-equilibrium QCD. In this paper, by using closed-time path integral formalism, we derive the gauge invariant definition of the gluon to hadron fragmentation function in non-equilibrium QCD which is consistent with factorization theorem in non-equilibrium QCD from first principles.

    hep-phnucl-thPhys.Part.Nucl.Lett.(2017)·29 citations
13. 13*

    The QCD phase diagram in the presence of an external magnetic field: the role of the inverse magnetic catalysis

    Márcio Ferreira🇵🇹 · Pedro Costa🇵🇹 · Constança Providência🇵🇹

    The effect of an external magnetic field in QCD phase diagram, namely, in the the location of the critical end point (CEP) is investigated. Using the 2+1 flavor Nambu--Jona-Lasinio model with Polyakov loop, it is shown that when an external magnetic field is applied its effect on the CEP depends on the strength of the coupling. If the coupling depends on the magnetic field, allowing for inverse magnetic catalysis, the CEP moves to lower chemical potentials eventually disappearing, and the chiral restoration phase transition is always of first order.

    hep-ph6 citations
14. 14*

    Hidden Cosmic-Ray Accelerators as an Origin of TeV-PeV Cosmic Neutrinos

    Kohta Murase (PSU)🇺🇸 · Dafne Guetta (OAR)🇮🇱 · Markus Ahlers (UW-Madison)🇺🇸

    The latest IceCube data suggest that the all-flavor cosmic neutrino flux may be as large as 10^-7 GeV/cm^2/s/sr around 30 TeV. We show that, if sources of the TeV-PeV neutrinos are transparent to gamma rays with respect to two-photon annihilation, strong tensions with the isotropic diffuse gamma-ray background measured by Fermi are unavoidable, independently of the production mechanism. We further show that, if the IceCube neutrinos have a photohadronic (pgamma) origin, the sources are expected to be opaque to 1-100 GeV gamma rays. With these general multimessenger arguments, we find that the latest data suggest a population of cosmic-ray accelerators hidden in GeV-TeV gamma rays as a neutrino origin. Searches for x-ray and MeV gamma-ray counterparts are encouraged, and TeV-PeV neutrinos themselves will serve as special probes of dense source environments.

    ↳ astro-ph.HEastro-ph.COhep-phPRL(2016)·417 citations
15. 15*

    Hybrid star structure with the Field Correlator Method

    G. F. Burgio🇮🇹 · D. Zappala' (INFN Sezione di Catania)🇮🇹

    We explore the relevance of the color-flavor locking phase in the equation of state (EoS) built with the Field Correlator Method (FCM) for the description of the quark matter core of hybrid stars. For the hadronic phase, we use the microscopic Brueckner-Hartree-Fock (BHF) many-body theory, and its relativistic counterpart, i.e. the Dirac-Brueckner (DBHF). We find that the main features of the phase transition are directly related to the values of the quark-antiquark potential $V_1$, the gluon condensate $G_2$ and the color-flavor superconducting gap $\Delta$. We confirm that the mapping between the FCM and the CSS (constant speed of sound) parameterization holds true even in the case of paired quark matter. The inclusion of hyperons in the hadronic phase and its effect on the mass-radius relation of hybrid stars is also investigated.

    ↳ nucl-thastro-ph.SRhep-phEPJA(2016)·19 citations
16. 16*

    Quantum Gravity Constraints from Unitarity and Analyticity

    Brando Bellazzini🇫🇷 · Clifford Cheung🇺🇸 · Grant N. Remmen🇺🇸

    We derive rigorous bounds on corrections to Einstein gravity using unitarity and analyticity of graviton scattering amplitudes. In $D\ge 4$ spacetime dimensions, these consistency conditions mandate positive coefficients for certain quartic curvature operators. We systematically enumerate all such positivity bounds in $D=4$ and $D=5$ before extending to $D\ge 6$. Afterwards, we derive positivity bounds for supersymmetric operators and verify that all of our constraints are satisfied by weakly-coupled string theories. Among quadratic curvature operators, we find that the Gauss-Bonnet term in $D\ge 5$ is inconsistent unless new degrees of freedom enter at the natural cutoff scale defined by the effective theory. Our bounds apply to perturbative ultraviolet completions of gravity.

    ↳ hep-thhep-phPRD(2016)·173 citations
17. 17*

    Dark matter searches

    Laura Baudis🇨🇭

    One of the major challenges of modern physics is to decipher the nature of dark matter. Astrophysical observations provide ample evidence for the existence of an invisible and dominant mass component in the observable universe, from the scales of galaxies up to the largest cosmological scales. The dark matter could be made of new, yet undiscovered elementary particles, with allowed masses and interaction strengths with normal matter spanning an enormous range. Axions, produced non-thermally in the early universe, and weakly interacting massive particles (WIMPs), which froze out of thermal equilibrium with a relic density matching the observations, represent two well-motivated, generic classes of dark matter candidates. Dark matter axions could be detected by exploiting their predicted coupling to two photons, where the highest sensitivity is reached by experiments using a microwave cavity permeated by a strong magnetic field. WIMPs could be directly observed via scatters off atomic nuclei in underground, ultra low-background detectors, or indirectly, via secondary radiation produced when they pair annihilate. They could also be generated at particle colliders such as the LHC, where associated particles produced in the same process are to be detected. After a brief motivation and an introduction to the phenomenology of particle dark matter detection, I will discuss the most promising experimental techniques to search for axions and WIMPs, addressing their current and future science reach, as well as their complementarity.

    ↳ astro-ph.COhep-phAnnalen Phys.(2016)·40 citations
18. 18*

    Axion as a cold dark matter candidate: Analysis to third order perturbation for classical axion

    Hyerim Noh🇰🇷 · Jai-chan Hwang🇰🇷 · Chan-Gyung Park🇰🇷

    We investigate aspects of axion as a coherently oscillating massive classical scalar field by analyzing third order perturbations in Einstein's gravity in the axion-comoving gauge. The axion fluid has its characteristic pressure term leading to an axion Jeans scale which is cosmologically negligible for a canonical axion mass. Our classically derived axion pressure term in Einstein's gravity is identical to the one derived in the non-relativistic quantum mechanical context in the literature. We show that except for the axion pressure term, the axion fluid equations are exactly the same as the general relativistic continuity and Euler equations of a zero-pressure fluid up to third order perturbation. The general relativistic density and velocity perturbations of the CDM in the CDM-comoving gauge are exactly the same as the Newtonian perturbations to the second order (in all scales), and the pure general relativistic corrections appearing from the third order are numerically negligible (in all scales as well) in the current paradigm of concordance cosmology. Therefore, here we prove that, in the super-Jeans scale, the classical axion can be handled as the Newtonian CDM fluid up to third order perturbation. We also show that the axion fluid supports the vector-type (rotational) perturbation from the third order. Our analysis includes the cosmological constant.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2015)·7 citations
19. 19*

    Single-Superfield Helical-Phase Inflation

    Sergei V. Ketov🇯🇵 · Takahiro Terada🇯🇵

    Large-field inflation in supergravity requires the approximate global symmetry needed to protect flatness of the scalar potential. In helical-phase inflation, the U(1) symmetry of the Kahler potential is assumed, the phase part of the complex scalar of a chiral superfield plays the role of inflaton, and the radial part is strongly stabilized. The original model of helical phase inflation, proposed by Li, Li and Nanopoulos (LLN), employs an extra (stabilizer) superfield. We propose a more economical new class of the helical phase inflationary models without a stabilizer superfield. As the specific examples, the quadratic, the natural, and the Starobinsky-type inflationary models are studied in our approach.

    ↳ hep-thastro-ph.COhep-phPLB(2016)·14 citations
20. 20*

    Manifestations of dark matter and variations of fundamental constants in atoms and astrophysical phenomena

    Y. V. Stadnik🇦🇺 · V. V. Flambaum🇦🇺

    We present an overview of recent developments in the detection of light bosonic dark matter, including axion, pseudoscalar axion-like and scalar dark matter, which form either a coherently oscillating classical field or topological defects (solitons). We emphasise new high-precision laboratory and astrophysical measurements, in which the sought effects are linear in the underlying interaction strength between dark matter and ordinary matter, in contrast to traditional detection schemes for dark matter, where the effects are quadratic or higher order in the underlying interaction parameters and are extremely small. New terrestrial experiments include measurements with atomic clocks, spectroscopy, atomic and solid-state magnetometry, torsion pendula, ultracold neutrons, and laser interferometry. New astrophysical observations include pulsar timing, cosmic radiation lensing, Big Bang nucleosynthesis and cosmic microwave background measurements. We also discuss various recently proposed mechanisms for the induction of slow `drifts', oscillating variations and transient-in-time variations of the fundamental constants of Nature by dark matter, which offer a more natural means of producing a cosmological evolution of the fundamental constants compared with traditional dark energy-type theories, which invoke a (nearly) massless underlying field. Thus, measurements of variation of the fundamental constants gives us a new tool in dark matter searches.

    ↳ physics.atom-phastro-ph.COhep-phhep-th+110 citations
21. 21*

    Distance Priors from \emph{Planck} 2015 data

    Qing-Guo Huang🇨🇳 · Ke Wang🇨🇳 · Sai Wang🇨🇳

    We update the distance priors by adopting $Planck\text{TT,TE,EE}+\text{lowP}$ data released in 2015, and our results impose at least $30\%$ tighter constraints than those from $Planck\text{TT}+\text{lowP}$. Combining the distance priors with the combination of supernova Union~2.1 compilation of 580 SNe (Union~2.1) and low redshift Baryon Acoustic Oscillation (BAO) data, we constrain the cosmological parameters in the freely binned dark energy (FBDE) and FBDE$+{\Omega }_k$ models respectively, and find that the equations of state of dark energy in both models are consistent with $w=-1$. Furthermore, we show that the tension with the BAO data at $z=2.34$ from Ly$\alpha$ forest (Ly$\alpha$F) auto-correlation and Combined Ly$\alpha$F cannot be relaxed in the FBDE and FBDE$+{\Omega }_k$ models.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2015)·44 citations
22. 22*

    Resonance Production and $\pi \pi$ S-wave in ${\pi }^{-}+p\to {\pi }^{-}{\pi }^{-}{\pi }^{+}+p_{recoil}$ at 190 GeV/c

    C. Adolph🇩🇪 · R. Akhunzyanov🇷🇺 · M.G. Alexeev🇮🇹 · G.D. Alexeev🇷🇺 · A. Amoroso🇮🇹 · V. Andrieux🇫🇷 · V. Anosov🇷🇺 · W. Augustyniak🇵🇱 · A. Austregesilo🇩🇪 · C.D.R. Azevedo🇵🇹 · B. Badełek🇵🇱 · F. Balestra🇮🇹 and 198 other authors

    The COMPASS collaboration has collected the currently largest data set on diffractively produced ${\pi }^{-}{\pi }^{-}{\pi }^{+}$ final states using a negative pion beam of 190 GeV/c momentum impinging on a stationary proton target. This data set allows for a systematic partial-wave analysis in 100 bins of three-pion mass, $0.5<m_{3\pi }<2.5$ GeV/c${}^2$ , and in 11 bins of the reduced four-momentum transfer squared, $0.1<t<1.0$ (GeV/c)${}^2$ . This two-dimensional analysis offers sensitivity to genuine one-step resonance production, i.e. the production of a state followed by its decay, as well as to more complex dynamical effects in nonresonant $3\pi$ production. In this paper, we present detailed studies on selected $3\pi$ partial waves with $J^{PC}=0^{-+}$, $1^{++}$, $2^{-+}$, $2^{++}$, and $4^{++}$. In these waves, we observe the well-known ground-state mesons as well as a new narrow axial-vector meson $a_1(1420)$ decaying into $f_0(980)\pi$. In addition, we present the results of a novel method to extract the amplitude of the ${\pi }^{-}{\pi }^{+}$ subsystem with $I^G{J}^{PC}=0^{+}{0}^{++}$ in various partial waves from the ${\pi }^{-}{\pi }^{-}{\pi }^{+}$ data. Evidence is found for correlation of the $f_0(980)$ and $f_0(1500)$ appearing as intermediate ${\pi }^{-}{\pi }^{+}$ isobars in the decay of the known $\pi (1800)$ and ${\pi }_2(1880)$.

    ↳ hep-exhep-phPRD(2017)·105 citations
23. 23*

    A method for comparing non-nested models with application to astrophysical searches for new physics

    Sara Algeri🇬🇧 · Jan Conrad🇸🇪 · David A. van Dyk🇬🇧

    Searches for unknown physics and decisions between competing astrophysical models to explain data both rely on statistical hypothesis testing. The usual approach in searches for new physical phenomena is based on the statistical Likelihood Ratio Test (LRT) and its asymptotic properties. In the common situation, when neither of the two models under comparison is a special case of the other i.e., when the hypotheses are non-nested, this test is not applicable. In astrophysics, this problem occurs when two models that reside in different parameter spaces are to be compared. An important example is the recently reported excess emission in astrophysical $\gamma$-rays and the question whether its origin is known astrophysics or dark matter. We develop and study a new, simple, generally applicable, frequentist method and validate its statistical properties using a suite of simulations studies. We exemplify it on realistic simulated data of the Fermi-LAT $\gamma$-ray satellite, where non-nested hypotheses testing appears in the search for particle dark matter.

    ↳ physics.data-anastro-ph.HEhep-exhep-ph+1MNRAS(2016)·17 citations
24. 24*

    Combined analysis of charm-quark fragmentation-fraction measurements

    Mykhailo Lisovyi🇩🇪 · Andrii Verbytskyi🇩🇪 · Oleksandr Zenaiev🇩🇪

    A summary of measurements of the fragmentation of charm quarks into a specific hadron is given. Measurements performed in photoproduction and deep inelastic scattering in $e^{\pm }p$, $pp$ and $e^{+}{e}^{-}$ collisions are compared, using up-to-date branching ratios. Within uncertainties, all measurements agree, supporting the hypothesis that fragmentation is independent of the specific production process. Averages of the fragmentation fractions over all measurements are presented. The average has significantly reduced uncertainties compared to individual measurements.

    ↳ hep-exhep-phnucl-exEPJC(2016)·171 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.