挑战粒子物理标准模型：“超重”的W规范玻色子

<正>一、W玻色子在粒子物理发展过程中的地位提到W玻色子的历史,必须简要地回顾弱相互作用的发展过程。弱相互作用首先是从核β衰变(n→p+■+■_e)的观测中推断出来。在1935年,恩里科·费米(Enrico Fermi)率先提出了第一个弱相互作用理论,其相互作用的形式与电磁相互作用的形式类似,并以所谓的费米常数(GF)为此相互作用的特征耦合。通过比较电磁与弱相互作用的大小,     

楔形瓣状结构对正向注入型Si-LED发光特性的影响

基于标准CMOS工艺的p+源/漏区和n阱,设计了两种楔形瓣状结构的正向注入型硅基发光二极管(Si-LED),采用UMC 0.18μm 1P6M CMOS工艺设计制备.测试结果表明,正向注入型p+/n-well二极管的发射波长位于近红外波段,峰值波长在l 130 nm附近,且工作电压小于2V,与标准CMOS电路兼容.其中,八瓣结构的Si-LED (TS2)在200 mA时的发光功率可达1 200 nW,且未出现饱和,而注入电流为40 mA时的最大功率转换效率达5.8×10-6,约为四瓣结构器件(TSl)的2倍.所研制的Si-LED具有工作电压低、转换效率高等优点,有望在光互连领域得到应用.     

Flavor-Changing Neutral-Current Production of t-c in Association with a Neutral Top-Higgs at LHC in the Topcolor-Assisted Technicolor Model

In the framework of the topcolor-assisted technicolor （TC2） model we investigate the flavor-changing neutral-current production pp→ t-chto at the Large Hadron Collider （LHC）, which proceeds through the parton-level processes gg→ t-chto , uu→ t-chto and d-d → t-chto . We calculate the production rate and present the distributions of the transverse momenta and the invarient mass of the neutral top-higgs. It is found that the cross section of pp→ t-chto can reach a few hundreds of fb in a large part of the allowed parameter space. Considering the main decay mode of top-higgs for mht〈2mt, we find that such a production may provide copious events. In the case of unobservation, the LHC can set meaningful constraints on the TC2 model.     

Probing light DM via the Migdal effect with spherical proportional counter

Owing to its low electronic noise and flexible target materials, the Spherical Proportional Counter(SPC)with a single electron detection threshold can be utilized to search for sub-GeV dark matter(DM). In this study, we investigate the prospects for light DM direct detection via the DM-nucleus Migdal effect in the DARKSPHERE detector. We consider different DM velocity distributions and momentum-transfer effects. For Xenon and Neon targets, we find that the DM mass mDM can be probed down to as lo...