New constraints on “INO” masses from cosmology (I). Supersymmetric “inos”

In this first paper we derive new constraints on gravitino and photino masses in big bang cosmology. First, in the context of induced supersymmetry breaking we calculate explicitly the gravitino decay rate into gauginos, and find that in the absence of significant dilution the gravitino mass must be ?5 × 10⁴ GeV in order not to affect nucleosynthesis. We also find in this case that constraints in the lightest R-odd particle, the photino, differ significantly from earlier bounds based on analogy with stable heavy neutrino bounds in the standard model, due to out of equilibrium gravitino decay. In order to avoid both these constraints the gravitino distribution must be severely suppressed. If this is due to inflation, it must occur at a scale ?10¹⁰?10¹¹ GeV.     

Riccion from higher-dimensional space-time with D-dimensional sphere as a compact manifold and one-loop renormalization

Lagrangian density of riccions is obtained with the quartic self-interacting potential using higher-derivative gravitational action in (4 +D)-dimensional space-time withS ^D as a compact manifold. It is found that the resulting four-dimensional theory for riccions is one-loop multiplicatively renormalizable. Renormalization group equations are solved and its solutions yield many interesting results such as (i) dependence of extra dimensions on the enegy mass scale showing that these dimensions increase with the increasing mass scale up toD = 6, (ii) phase transition at 3.05 × 10¹⁶ GeV and (iii) dependence of gravitational and other coupling constants on energy scale. Results also suggest that space-time above 3.05 × 10¹⁶ GeV should be fractal. Moreover, dimension of the compact manifold decreases with the decreasing energy mass scale such thatD = 1 at the scale of the phase transition. Results imply invisiblity of S¹ at this scale (which is 3.05 × 10¹⁶ GeV).     

Renormalization of seesaw neutrino masses in the standard model with two-Higgs doublets

Using the theoretical ambiguities inherent in the seesaw mechanism, we derive the new analytic expressions for both quadratic and linear seesaw formulae for neutrino masses at low energies, with either up-type quark masses or charged lepton masses. This is possible through full radiative corrections arising out of the renormalizations of the Yukawa couplings, the coefficients of the neutrino-mass-operator in the standard model with two-Higgs doublets, and also the QCD-QED rescaling factors below the top-quark mass scale, at one-loop level. We also investigate numerically the unification of top-b-τ Yukawa couplings at the scale M ₁=0.59×10⁸ GeV for a fixed value of tan β=58.77, and then evaluate the seesaw neutrino masses which are too large in magnitude to be compatible with the presently available solar and atmospheric neutrino oscillation data. However, if we consider a higher but arbitrary value of M ₁=0.59×10¹¹ GeV, the predictions from linear seesaw formulae with charged lepton masses, can accommodate simultaneousely both solar atmospheric neutrino oscillation data.     

A supersymmetric gut

We propose a grand unified supersymmetric theory based on SU(5) with spontaneously broken supersymmetry. The theory (really a class of theories) is completely realistic. In particular, supersymmetry partners of ordinary fermions and bosons are heavy. The model requires one fine-tuning in order to render the color triplet partners of the Higgs fields (which mediate proton decay) superheavy. This fine-tuning is stable against radiative corrections. At the tree level, the model contains two scales, the unification scale, of order 10¹⁶ GeV, and the supersymmetry breaking scale, of order 10¹⁰ GeV. The breaking of SU(2) × U(1) invariance arises as a radiative effect. The lightest of the new particles implied by supersymmetry are expected to have masses of order tens of GeV.     

Low-energy dilation

We study consequences of scale symmetry breaking in the QCD effective SU(2)×SU(2) chiral model. The mass of a pseudo-Goldstone boson dilation is estimated to be M_σ≅1 GeV and the upper bound to its lifetime τ_σ⩽4×10⁻²⁸ s. We also show that the dilation gives a considerable contribution to the pion scalar radius.     

Integral energy spectrum of primary cosmic rays at high energies

The integral energy spectrum of primary cosmic rays has been obtained. In the energy range (2.4×10³−1.1×10⁵ GeV), the spectrum of all nuclei is consistent with a power law of indexγ=1.55±0.06 and the flux of all nuclei is:N(⩾E ₀)⋍(5.1±1.8)×10⁻¹×E ₀ ^−1.55 particles/cm² sterad. sec., whereE ₀ is in GeV. The spectrum of primaryα-particles in the energy range (4.4×10³−4.8×10⁴) GeV is also consistent with a power law of indexγ=1.71±0.12 and the flux is:N(⩾E ₀)=(4.2±1.4)×10⁻¹×E ₀ ^−1.71 , particles per cm² sterad. sec, whereE ₀ is in GeV.     

A light neutral intermediate vector boson without large e+e−→ μ+μ− asymmetries

An effective SU(2)×U(1)×U(1)' electroweak theory is shown to permit the occurence of a pair of neutral intermediate vector bosons with masses 40 GeV?m_light?70 GeV, m^W.S._Z⁰<m_heavy?100 GeV. Neutrino neutral current interactions are shown to be the same as in the standard electroweak model, and e⁺e^?→μ⁺μ^? forward-backward asymmetries are within experimental bounds for m_light?40 GeV.     

Energy spectrum and mass composition of primary cosmic rays in the vicinity of the “knee” in a model with two types of sources

An analysis of the data on the spectra of cosmic rays in the context of the proposed model with two types of sources suggests that the main contribution to the spectrum of all particles in the range of 10⁵?10⁷ GeV is made by the sources in which the exponent in the spectrum of particles’ generation p ≈ 2.85. The complex structure of the spectrum in the vicinity of the “knee” may arise owing to the presence of an additional supernova-type source that accelerates the particles to the energies of ～3 × 10⁴ Z GeV if the energy output of this source is ～2 × 10⁴⁸ erg/source.     

Discrete scale invariance and ln(B) periodic quantum oscillations in topological semimetals

The Panda X-4T experiment, a 4-ton scale dark matter direct detection experiment, is being planned at the China Jinping Underground Laboratory. In this paper we present a simulation study of the expected background in this experiment. In a 2.8-ton fiducial mass and the signal region between 1-10 keV electron equivalent energy, the total electron recoil background is found to be 4.9 × 10~(-5) kg~(-1) d~(-1) keV~(-1). The nuclear recoil background in the same region is 2.8 × 10~(-7) kg~(-1) d~(-1) keV~(-1). With an exposure of 5.6 ton-years, the sensitivity of Panda X-4 T could reach a minimum spin-independent dark matter-nucleon cross section of 6 × 10~(-48) cm~2 at a dark matter mass of 40 Ge V/c~2.     

Test of Higgs boson nature in e+e−→HHZ

The process e⁺e^?→HHZ is strongly dependent on the Higgs boson couplings HZZ, HHZZ and HHH, and provides therefore a test of the Higgs assignment to gauge group representations. The cross section varies between 5 × 10^?38 and 10^?39 cm² for Higgs masses between 5GeV and 40 GeV in the Weinberg-Salam model.     

A search for new massive particles

We have searched for an almost stable, charged particle produced in 400 GeV proton-nucleus collisions. A total of 5 × 10¹⁰ light secondary particles were sampled in a secondary beam of 70 GeV/c momentum. If a 4.5 to 6.0 GeV mass particle is produced with a cross section comparable with the production cross section of the upsilon then this experiment places an upper limit on the lifetime of such a particle of about 5 × 10^?8 s.     

大统一对禁闭弱作用规范模型的限制

本文基于两个条件:10¹⁴GeV≤M_u≤10¹⁹GeV,300GeV≤Λ_hc≤1TeV,得到在禁闭弱作用规范模型中SU(N)超色规范群满足N≤3;大统一规范群的可能候选者为:SU(N)N≥7,SU(N)×SU(N)N≥4,SO(14)和SO(18)。 关键词：     

A supersymmetricSU(5)×U(1) model with natural gauge hierarchy

We present a supersymmetricSU(5)×U(1) model. This model has the following features. The gauge hierarchy is naturally generated by the quadratically divergent nature of the Fayet-IliopoulosD term. TheSU(5)×U(1) gauge symmetry breaks uniquely intoSU(3) _W ×SU(2) _c ×U(1) _y at an energy scale of 10^17–18GeV. The non-vanishing vacuum expectation value of an auxiliary field component ofU(1) gauge vector multiplet induces the breaking ofSU(2) _W ×U(1) _y . It gives a mass of 10^2–3GeV to scalar quarks and scalar leptons at the tree level. The renormalization group analysis shows that the color fine structure constant α _C (M _W ) becomes somewhat small and the Weinberg angle sin²θ _W (M _W ) somewhat too large in a simple version of the model.     

Estimating the fraction of gamma quanta in the primary cosmic ray flux with energies of ∼1017 eV from the MSU EAS array data

Using data from the MSU EAS array and model calculations, we search for events with abnormally small fractions of muons with energies above 10 GeV in showers with particle numbers of >2 × 10⁷ and zenith angles of <30 degrees. We confirm with good statistical accuracy that the content of gamma quanta in the primary cosmic ray flux can be as high as 2% at energies of ～10¹⁷ eV.     

Muons in extensive air showers of energies E 0=1016.6–1019.8 eV

Data on muons with the threshold energy E _μ≈1.0×secθ GeV in extensive air showers of energies E ₀≥4×10¹⁶ eV measured on the Yakutsk and Akeno arrays are jointly analyzed. The results are compared with the calculations by the quark-gluon-string model with jets. It is shown that this model does not contradict the data measured for energies E ₀≤10¹⁸ eV on both arrays under the assumption that the primary particle composition differs from the composition where heavy nuclei dominate over protons. Experimental data for energies E ₀≥3×10¹⁸ eV indicate that the shower development differs from that predicted by the quark-gluon-string model with jets.     

Supersymmetric relics from the big bang

We consider the cosmological constraints on supersymmetric theories with a new, stable particle. Circumstantial evidence points to a neutral gauge/Higgs fermion as the best candidate for this particle, and we derive bounds on the parameters in the lagrangian which govern its mass and couplings. One favored possibility is that the lightest neutral supersymmetric particle is predominantly a photino $\text{～}\text{γ}$ with mass above $\text{1}\text{2}$ GeV, while another is that the lightest neutral supersymmetric particle is a Higgs fermion with mass above 5 GeV or less than O(100) eV. We also point out that a gravitino mass of 10 to 100 GeV implies that the temperature after completion of an inflationary phase cannot be above 10¹⁴ GeV, and probably not above 3 × 10¹² GeV. This imposes constraints on mechanisms for generating the baryon number of the universe.     

Constraints on light particles from stellar evolution

We examine the constraints imposed on the numbers and interactions of light particles by our understanding of the late stages of stellar evolution, including red giants, carbon-burning stars and cooling neutron stars. We show that these astrophysical considerations restrict the number of neutrino types to be less than 10^+2±1. This result complements the standard constraints from cosmological nucleosynthesis, which was unable to exclude numbers of neutrinos between a few thousand and the best particle physics limit of order 10⁵. We also investigate the constraints on supersymmetric theories with a light photino and gravitino, finding that the supersymmetry breaking scale parameter f>O(100GeV) and the selectron masses are >20 to 40 GeV. Finally, we study energy-loss rates by majoron and invisible axion emission.     

Another calculation of the Higgs mass and the top mass from the principles of H. B. Nielsen: m H ≅ 163GeV for M t ≅ 190GeV

We calculate the Higgs mass and the top mass starting from the principle that there are two, essentially degenerate minima in the Higgs effective potential; the second is at about the Planck energy scale M _P = 1.2 × 10¹⁹ GeV. Thus the parameter of the quartic self-coupling λ _h vanishes, as does β _λH at M _P. The new element is the addition of a quantum interaction term which couples the square of the Higgs field to the square of a pseudoscalar field, in the domain of the energy scale between about 10¹⁴ GeV and M _P. We modify β _λH at one loop. The pseudoscalar field which is introduced may be the field which is responsible for a spontaneous breakdown of discrete symmetry — for CP noninvariance at an energy scale of (10¹⁵–10¹⁶) GeV. The result is then a closer value for m _H ? 163 GeV for the top pole-mass M _t ? 190 GeV; both values are now close to the electroweak scale parameter $\langle {\phi _H}\rangle /\sqrt 2 = 175{\text{ GeV}}$ . In terms of dimensionless running coupling parameters, which determine the masses near to the electroweak scale, we get $\sqrt {{\lambda _H}} \cong 0.06$ and $gt/\sqrt 2 \cong 0.72$ , values that are close to each other and close to unity.     

Signatures of lower-scale gauge coupling unification in the standard model due to extended Higgs sector

The gauge coupling unification can be achieved at a unification scale around 5×10¹³ GeV if the Standard Model scalar sector is extended with extra Higgs-like doublets. The relevant new scalar degrees of freedom in the form of chiral Z* and W* vector bosons might “be visible” already at about 700 GeV. Their eventual preferred coupling to the heavy quarks explains the non observation of these bosons in the first LHC run and provides promising expectation for the second LHC run.     

Search for long-lived particles in 200 GeV/c proton-nucleon collisions

A search for long-lived particles (τ ? 10^?8 sec), with changes $\text{±}\text{2}\text{3}\text{, ± 1, ±}\text{4}\text{3}\text{and}\text{± 2}$, produced in 200 GeV pN collisions was performed at the CERN-SPS in a secondary beam equipped with superconducting r.f. separators. Upper limits were obtained for the production of long-lived hadrons and leptons. For charge - 1 particles the limits are at the level of 10^?7 of the pions at a mass m = 0.2 GeV and reach the 10^?11 level from $\text{3}\text{to}\text{8}\text{GeV}$. The production of light antinuclei was measured. The cross sections for ³He production are (1.3 ± 0.3) and (1.9 ± 0.3) × 10^?34 cm²/sr · GeV/c at 21 and 47.4 GeV/c respectively; for t the cross section is (7.6 ± 0.9) × 10^?34 cm²/sr · GeV/c at 23.7 GeV/c.