我们报告的结果,从一个盲分析的最终数据与低温暗物质搜索实验(CDMS II)在苏丹地下实验室,明尼苏达州,美国。本工作分析了612 kg-天的总原始暴露量。我们在信号区域观察到两个事件;根据我们的背景估计,观察到两个或更多背景事件的概率为23%。在90%的置信水平下,这些数据为质量为70 GeV/c^2的弱相互作用大质量粒子(WIMP)-核子弹性散射自旋无关截面设定了7.0 × 10 ^{-44} cm ^2的上限。将这个结果与CDMS II之前的所有数据结合起来,得出质量为70 GeV/c^2的WIMP与核子自旋无关截面的上限为3.8 × 10 ^{-44} cm ^2。我们还排除了新的参数空间,最近提出的非弹性暗物质模型。
英文摘要:
We report results from a blind analysis of the final data taken with the Cryogenic Dark Matter Search experiment (CDMS II) at the Soudan Underground Laboratory, Minnesota, USA. A total raw exposure of 612 kg-days was analyzed for this work. We observed two events in the signal region; based on our background estimate, the probability of observing two or more background events is 23%. These data set an upper limit on the Weakly Interacting Massive Particle (WIMP)-nucleon elastic-scattering spin-independent cross-section of 7.0x10^{-44} cm^2 for a WIMP of mass 70 GeV/c^2 at the 90% confidence level. Combining this result with all previous CDMS II data gives an upper limit on the WIMP-nucleon spin-independent cross-section of 3.8x10^{-44} cm^2 for a WIMP of mass 70 GeV/c^2. We also exclude new parameter space in recently proposed inelastic dark matter models.
低温暗物质搜索实验(CDMS)采用低温Ge和Si探测器通过目标核的弹性散射来探测WIMP。最后一次分析中,锗暴露量为397.8千克-天,没有观测到任何候选事件,因此,当WIMP质量为60 GeV时,与自旋无关的WIMP-核子截面的上限为6.6 x 10 ^{-44} cm ^2(如果包括之前的CDMS Soudan数据,则为4.6 x 10^{-44} cm ^2)。将讨论当前分析的表面事件抑制能力的改进,其中锗暴露比上次分析中使用的暴露大2.5倍。为了将灵敏度提高到超过1 x 10^{-44} cm ^2的基准,研制了新的1英寸厚的探测器。由六个这种探测器组成的第一个塔已成功地安装在苏丹场址。这些探测器将用于15 kg的SuperCDMS级,预期对自旋无关的WIMP-核子弹性散射截面的灵敏度为5 x 10^{-45} cm ^2。此外,CDMS协作组已经开始寻找非WIMP暗物质粒子的特征,这可能解释DAMA观测到的年度调制特征。
Combined Limits on WIMPs from the CDMS and EDELWEISS Experiments
CDMS和EDELWEISS的合作结合了他们使用低温锗探测器直接搜索暗物质的结果。总数据集代表614 kg.d当量接触。在实验之间交换数据之前,选择了一种简单的组合方法。结果解释的限制自旋无关的WIMP核子截面。对于质量为90 GeV/c^2的WIMP,这种分析是最灵敏的,在90% CL下排除了3.3 x 10^{-44} cm ^2的截面。在更高的WIMP质量下,这种组合使单个极限提高了1.6倍,高于700 GeV/c^2。结合数据的替代方法为WIMP质量的某些范围提供了更强的约束,而为其他范围提供了更弱的约束。
We present constraints on the existence of weakly interacting massive particles (WIMPs) from an 11 kg-day target exposure of the DAMIC experiment at the SNOLAB underground laboratory. The observed energy spectrum and spatial distribution of ionization events with electron-equivalent energies $>$200 eV$_{\rm ee}$ in the DAMIC CCDs are consistent with backgrounds from natural radioactivity. An excess of ionization events is observed above the analysis threshold of 50 eV$_{\rm ee}$. While the origin of this low-energy excess requires further investigation, our data exclude spin-independent WIMP-n…
The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) searches for interactions between dark matter particles and germanium nuclei in cryogenic detectors. The experiment has achieved a low energy threshold with improved sensitivity to low-mass (<10 GeV/c$^2$) dark matter particles. We present an analysis of the final CDMSlite data set, taken with a different detector than was used for the two previous CDMSlite data sets. This analysis includes a data "salting" method to protect against bias, improved noise discrimination, background modeling, and the use of profile li…
We present the first limits on inelastic electron-scattering dark matter and dark photon absorption using a prototype SuperCDMS detector having a charge resolution of 0.1 electron-hole pairs (CDMS HVeV, a 0.93 gram CDMS HV device). These electron-recoil limits significantly improve experimental constraints on dark matter particles with masses as low as 1 MeV/$\mathrm{c^2}$. We demonstrate a sensitivity to dark photons competitive with other leading approaches but using substantially less exposure (0.49 gram days). These results demonstrate the scientific potential of phonon-mediated semiconduc…
Dark Matter Search Results from the Complete Exposure of the PICO-60 C$_3$F$_8$ Bubble Chamber
最后的结果报告的PICO-60 C $_3$ F $_8$暗物质探测器,一个泡室充满了52公斤的C $_3$ F $_8$位于SNOLAB地下实验室的操作。该室在低至1.2 keV的热力学阈值下操作,而不损失稳定性。在2.45 keV阈值下获得了新的盲态1404 kg-天暴露量,预期总背景速率与之前在3.3 keV下的1167 kg-天暴露量大致相同。这种增加的曝光部分是通过新的光学跟踪分析来实现的,以更好地识别探测器壁附近的事件,从而允许更大的基准体积。这些结果设置了最严格的直接检测约束的日期在2.5 $\times$ 10 $^{-41}$ cm $^2$的25 GeV的WIMP质子自旋相关的横截面,并改善了以前的PICO结果为3-5 GeV的WIMP的数量级。