论文标题
II型Seesaw Triplet标量对中微子三叉戟散射的影响
Type-II Seesaw Triplet Scalar Effects on Neutrino Trident Scattering
论文作者
论文摘要
在II型SEESAW模型中，引入了具有非零真空期望值（VEV）$v_Δ$的Electroweak三重标量表标量$δ$，以促进产生小型中微子质量。非零$v_δ$还通过electroweak $ρ$参数影响w质量，使其如标准模型（SM）所预测的小于1。 $δ$中的组件字段出现了额外的贡献，以减少SM稀有中微子三叉戟散射横截面。这些字段还诱导SM中不存在新过程，例如$ l_i \ to \ overline {l_j} l_k l_l $和$ l_i \ tol_jγ$。在这些过程上存在严重限制，这些过程限制了对中微子三叉戟散射和$ρ$参数的影响，因此限制了$ρ$参数。 CDF新近测量的W质量使$ρ$参数的中心值大于1，甚至比以前预期的大。结合了中性s中微子双β衰减，直接中微子质量和振荡数据，我们发现$v_δ$的下限是三重量表标量质量$m_δ$，$v_Δ>（6.3 \ sim 8.4）\ mathrm {ev ev}（100 \ mathrm {gev}/m_Δ）$。要在此型号中对$ρ$产生重大影响，$v_δ$需要在GEV左右的范围内。但是，这意味着一个非常小的$m_δ$被数据排除在外。我们得出的结论是，可以忽略三胞胎VEV $v_δ$对w质量的影响。我们还发现，在3 $σ$的水平下，II型SEESAW与SM中微子三叉戟散射横截面预测的比率的偏差降低为1以下，但仅限于0.98。
In Type-II seesaw model, an electroweak triplet scalar field $Δ$ with a non-zero vacuum expectation value (vev) $v_Δ$ is introduced to facilitate the generation of small neutrino masses. A non-zero $v_Δ$ also affects the W mass through the electroweak $ρ$ parameter, making it to be less than 1 as predicted by standard model (SM). The component fields in $Δ$ come along introduce additional contributions to reduce the SM rare neutrino trident scattering cross section. These fields also induce new processes not existed in SM, such as $l_i \to \overline{ l_j} l_k l_l$ and $l_i \to l_j γ$. There are severe constraints on these processes which limit the effects on neutrino trident scattering and the $ρ$ parameter and therefore the W mass. The newly measured W mass by CDF makes the central value of $ρ$ parameter to be larger than 1, even larger than previously expected. Combining neutrinoless double beta decay, direct neutrino mass and oscillation data, we find a lower limit for $v_Δ$ as a function of the triplet scalar mass $m_Δ$, $v_Δ> (6.3 \sim 8.4) \mathrm{eV} (100 \mathrm{GeV}/m_Δ)$. To have significant effect on $ρ$ in this model, $v_Δ$ needs to be in the range of a GeV or so. However this implies a very small $m_Δ$ which is ruled out by data. We conclude that the effect of triplet vev $v_Δ$ on the W mass can be neglected. We also find that at 3$σ$ level, the deviation of the ratio for Type-II Seesaw to SM neutrino trident scattering cross section predictions is reduced to be below 1, but is restricted to be larger than 0.98.
