14601338
The mesonic fluctuations and corrections in the chiral symmetry breaking vacuum
Abstract The mesonic quantum fluctuations and their corrections on the chiral condensate and pion polarization function are investigated in the self-consistent scheme of SU(2) Nambu–Jona-Lasinio model by exactly calculating the next-to-leading order (NLO) Feynman diagrams in 1/ N c expansion. While the fluctuations and corrections depend strongly on the meson's three-momentum cut-off Λ M , no chiral symmetry restoration is found since the cancellation between the NLO and the one-quark-loop diagram with quark mass deviated from the mean-field value.
119992531
Correlation between transverse energy and zero-degree energy in relativistic heavy-ion collisions
Based on the participant-spectator picture, applying the multisource model, the distributions of the zero-degree energy (EZD) and the transverse energy (ET) in the projectile-fragmentation region in relativistic heavy-ion collisions are calculated. The correlation between ET and EZD distributions is also analyzed. For collisions of 60A and 200A GeV 16O with different targets our results fit the new data of WA80 at CERN very well.
123725926
Quark propagator with a quark mass term in the color-superconducting phase
121242440
FITTING THE EMC PHENOMENON WITH A MODIFIED SCALE CHANGE MODEL
It is pointed out that when fitting the EMC experiments, as a modified version of the scale change model, two more factors based on theoretical considerations should be taken into account and probably the valence quark component has a different effective confinement scale from that of the sea quarks.
123880856
Phase-space quark counting rule
SummaryA simple quark counting rule based on the phase-space consideration suggested before is used to fit all 39 recent experimental data points on inclusive reactions. Parameter-free relations are found to agree with experiments. Excellent detail fits are obtained for 11 inclusive reactions.RiassuntoSi usa una semplice regola per contare i quark basata sull'uso dello spazio delle fasi suggerita prima per adattare 39 recenti punti sperimentali sulle reazioni inclusive. Si trova che le relazioni senza parametri sono in accordo con gli esperimenti. Si ottengono eccellenti adattamenti dei dettagli per 11 reazioni inclusive.РезюмеРанее предложенное простое правило вычисления кварков, основанное на рассмотрении фазового пространства, применяется для подгонки всех 39 недавних экспериментальных точек в инклюзивных реакциях. Определяются соотношения без параметров. Для 11 инклюзивных реакций получается хорошее согласие с экспериментами.
122953503
Nuclear Geometry and the ET-Distribution in High-Energy Heavy-Ion Collisions
Based on a geometric consideration, applying the multisource model the ET-distributions in the mid-rapidity and the target fragmentation regions in high-energy heavy-ion collisions are calculated. For different projectiles and targets the same set of parameters is used to fit the new data of CERN experiments.
119269487
Relatively large Theta13 from modification to the tri-bimaximal, bimaximal and democratic neutrino mixing matrices
A bstractInspired by the indication of a relatively large θ13 from accelerator and reactor neutrino oscillation experiments, we provide a systematic study of general modifications to the three well-studied neutrino mixing patterns, i.e., tri-bimaximal, bimaximal and democratic lepton mixing matrices. The correlation between θ13 and the other two neutrino mixing angles are derived for each types of additional rotations. Predictions on θ12 and θ23 are also studied. Our study shows that, although some types of additional rotations are already excluded by the current global fit data of neutrino mixing angles, several types of additional rotations still survive. Our results may provide a guideline for the model building in neutrino physics.
119282212
Pure Leptonic Gauge Symmetry, Neutrino Masses and Dark Matter
Abstract A possible extension of the Standard Model to include lepton number as local gauge symmetry is investigated. In such a model, anomalies are canceled by two extra fermions doublet. After leptonic gauge symmetry spontaneously broken, three active neutrinos may acquire non-zero Majorana masses through the modified Type-II seesaw mechanism. Constraints on the model from electro-weak precision measurements are studied. Due to the Z 2 discrete flavor symmetry, right-handed Majorana neutrinos can serve as cold dark matter candidate of the Universe. Constraint from dark matter relic abundance is calculated.
118352553
The Muon Magnetic Moment in the TeV Scale Seesaw Models
The reported discrepancy of the muon abnormal magnetic moment $a_\mu^{}$ has impacts on the low energy phenomenology. In this paper we calculate the corrections to $a_\mu$ in the standard model extended by the TeV scale seesaw models. We show that the correction induced by the type-I seesaw model is negative and of the order ${\cal O} (10^{-11})$, which can be neglected compared with $a_\mu^{\rm SM}$. The correction induced by the type-II seesaw model, which depends on the mass of the Higgs triplet $m_\Delta$ and the Yukawa coupling $Y_\Delta$, can be of the order ${\cal O}(10^{-10})$ and compensate for the discrepancy between $a_\mu^{\rm SM}$ and $a_{\mu}^{\rm exp}$. The correction induced by the type-III seesaw model is also negative and can be of the order ${\cal O}(10^{-10})$.
119308558
Vacuum stability and Higgs diphoton decay rate in the Zee-Babu model
A bstractAlthough recent Higgs data from ATLAS and CMS are compatible with a Standard Model (SM) signal at 2σ level, both experiments see indications for an excess in the diphoton decay channel, which points to new physics beyond the SM. Given such a low Higgs mass mH ~ 125 GeV, another sign indicating the existence of new physics beyond the SM is the vacuum stability problem, i.e., the SM Higgs quartic coupling may run to negative values at a scale below the Planck scale. In this paper, we study the vacuum stability and enhanced Higgs diphoton decay rate in the Zee-Babu model, which was used to generate tiny Majorana neutrino masses at two-loop level. We find that it is rather difficult to find overlapping regions allowed by the vacuum stability and diphoton enhancement constraints. As a consequence, it is almost inevitable to introduce new ingredients into the model, in order to resolve these two issues simultaneously.
119468037
Bi-Large Neutrino Mixing See-Saw Mass Matrix with Texture Zeros and Leptogenesis
We study constraints on neutrino properties from texture zeros in bi-large mixing See-Saw mass matrix and also from leptogenesis. Texture zeros may occur in the light (class a)) or in the heavy (class b)) neutrino mass matrices. Each of these two classes has 5 different forms which can produce non-trivial three generation mixing with at least one texture zero. We find that two types of texture zero mass matrices in both class a) and class b) can be consistent with present data on neutrino masses, mixing and produce the observed baryon asymmetry of the universe. None of the neutrinos can have zero masses with the lightest of the light neutrinos having a mass larger than about 0.039 eV for class a) and 0.002 eV for class b). In these models although CKM CP violating phase vanishes, non-zero Majorana phases, however, can exist and play an important role in producing the observed baryon asymmetry in our universe through leptogenesis mechanism. The requirement of producing the observed baryon asymmetry can further distinguish different models and also restrict the See-Saw scale to be in the range $10^{12}\sim 10^{15}$ GeV.