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arXiv 0705.4070hep-ph
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SNO +:标准太阳模型和自旋味旋进的预测

SNO+: predictions from standard solar models and spin flavour precession

Marco Picariello, João Pulido, S. Andringa, N. F. Barros, J. Maneira

摘要:

太阳中微子通量的时间变化,特别是在中低能区的变化,仍然是一个悬而未决的问题,如果它存在的话,很可能是由于在强烈的太阳活动和磁场的作用下,从活跃中微子到弱惰性中微子的磁矩跃迁引起的。我们研究了SNO+实验的前景,以解决这一重要问题,并区分目前被确定为对应于高(SSM I)和低(SSM II)重元素丰度的两类太阳能模型。我们还评估了这两个模型的预测氯实验事件率在标准LMA和LMA+旋味旋进(SFP)的情况。研究发现,经过三年的SNO+数据采集,pep通量测量将能够区分标准LMA和LMA+SFP情景,独立于哪个是正确的太阳模型。如果测量LMA速率,则可以在大于$4σ$时排除谐振$Δm^2_{01}$的具有$B_0 \sim 280kG$的SFP。低速率将表明新的物理特性,排除了3 $σ$时标准LMA溶液的所有90%允许范围,并且时间变异性将是SFP模型的强烈特征。CNO通量是两个SSM预测表现出最大差异的通量,因此在SNO+的测量对于支持其中一个或另一个很重要。在用pep确认LMA或SFP后,区别将更清楚,但在SSM I/LMA水平的CNO测量仍不利于SSM II,约为$3 σ$。我们的结论是,未来的PEP和CNO通量测量在SNO+和氯之间的一致性将有利于LMA+SFP方案或有利于SSM II的SSM I。

英文摘要:

Time variability of the solar neutrino flux especially in the low and intermediate energy sector remains an open question and, if it exists, it is likely to be originated from the magnetic moment transition from active to light sterile neutrinos at times of intense solar activity and magnetic field. We examine the prospects for the SNO+ experiment to address this important issue and to distinguish between the two classes of solar models which are currently identified as corresponding to a high (SSM I) and a low (SSM II) heavy element abundance. We also evaluate the predictions from these two models for the Chlorine experiment event rate in the standard LMA and LMA+Spin Flavour Precession (SFP) scenarios. It is found that after three years of SNO+ data taking, the pep flux measurement will be able to discriminate between the standard LMA and LMA+SFP scenarios, independently of which is the correct solar model. If the LMA rate is measured, SFP with $B_0 \sim 280kG$ for the resonant $Δm^2_{01}$ can be excluded at more than $4σ$. A low rate would signal new physics, excluding all the 90% allowed range of the standard LMA solution at 3$σ$, and a time variability would be a strong signature of the SFP model. The CNO fluxes are the ones for which the two SSM predictions exhibit the largest differences, so their measurement at SNO+ will be important to favour one or the other. The distinction will be clearer after LMA or SFP are confirmed with pep, but still, a CNO measurement at the level of SSM I/LMA will disfavour SSM II at about $3 σ$. We conclude that consistency between future pep and CNO flux measurements at SNO+ and Chlorine would either favour an LMA+SFP scenario or favour SSM II over SSM I.

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