49 Matching Annotations
  1. Apr 2024
    1. bunch crossings (events)

      "bunch crossings (events)"是指在高能物理实验,特别是加速器实验中,一束粒子被分成多个“束团”(bunches),这些束团在加速器中以接近光速的速度相对飞行。当两个束团在空间中的某个特定点“交叉”或对撞时,就会发生大量的粒子相互作用,产生大量的新粒子和辐射。这些粒子的相互作用和产生的事件就被称作“事件”(events)。在描述实验数据处理时,"bunch crossings (events)"指的是这些对撞产生的一个个独立的事件,每个事件都需要被单独记录和分析。

    1. pipeline

      一个有序的、自动化的工作流程,它定义了一系列步骤,这些步骤按照特定的顺序执行

    2. integrity

      正直,诚实,诚恳

    3. For data samples the available information is solely that coming from the reconstruction, but for simulation samples you can request both the reconstructed values of observables/variables and the generator-level (truth) values.

      difference of data samples and simulation samples

    4. Selections made at these last stages are also defined by users. Their outputs are saved to disk and later used to produce data files that will contain only the information that interests users.

      DaVinci 软件的功能

    5. pipeline

      "pipeline"一词指的是一个有序的、结构化的流程或步骤,用于处理数据并进行分析。它描述了从获取数据和模拟样本开始,到执行各种分析步骤,最终得出结果的一系列连贯的操作。在科研或数据分析的上下文中,"procedure pipeline"或简称为"pipeline"常用来指这样的流程。

    1. whereby the selection of candidates made in the second stage of the high level trigger, HLT2, is saved to disk and used directly by analysts, with no further offline reconstruction by Brunel.

      Turbo stream

    2. But, thanks to an enormous effort improving the reconstruction software both online and offline in between Run 1 and Run 2, the two reconstructions now perform identically.

      online and offline的重建能力基本一样,这是通过在Run1 & Run2之间对软件升级而实现的

    1. If you don’t know the stripping line you need, it’s usually best to ask the stripping coordinators of the working group you’ll be presenting your work to.

      如何确定使用的Stripping line

    2. Brunel application

      Triggered, raw data are reconstructed to transform the detector hits into objects such as tracks and clusters

    3. the data flow and the associated applications look like this:

      用MC数据来做触发的条件?

    4. Gauss is responsible

      Gauss application 的功能: 1. 用于调用由Pythia,POWHEG等提供的不同的MC模拟产生子 2. 用于调控EvtGen和Geant4。EvtGen 用于描述 模拟粒子,而 Geant4 用于模拟传播和 粒子通过检测器并与检测器相互作用。

    5. f most important file formats used in LHCb

      LHCb中重要的文件类型

    6. µDST format was designed to save space by storing only the information concerning the build candidates

      microDST的作用

    7. data flow designed to maximise the data-taking efficiency and data quality.

      data flow 被设计的目的

    8. the data must be processed very quickly because it’s arriving very quickly, and the data is complex so there’s a lot that can be done with it.

      过滤数据时考虑的两个关键点

    9. filter the data and try to keep only the events which contain something interesting

      对数据进行过滤所考虑的条件

  2. Mar 2024
    1. survive from

      怎么就 survive 了??

    2. Charmless backgrounds

      这里的 Charmless 是指不含 c,还是 hidden charm

    3. Potential fit bias is checked byperforming an ensemble test comprising 1000 pseudo-experiments, where signal is taken from the correspond-ing MC sample, and the PDF shapes are used to gen-erate background events. We obtain a Gaussian nor-malized residual distribution of unit width, and add itsmean and uncertainty in width in quadrature to cal-culate the systematic error.

      潜在拟合误差的检查

    4. The uncertainties due to PDF shapesare estimated by varying all the fixed shape parame-ters by their errors.

      如何考虑 PDF 形状带来的误差

    5. control sample

      为什么使用这个?是不是通常都使用一个 control sample?

    6. as obtained fromthe charged decay.

      没看懂

    7. PDF shape parameters

      这是什么

    8. we multiply the denominator by a factor of 12to account for K0 → K0S

      为什么是乘 1/2

    9. oss in efficiency on top of the smallsignal yield

      这是什么术语

    10. since we would need to tag the recoiling B candidate forthat, causing further loss in efficiency on top of the smallsignal yield.

      这为什么会造成信号的损失

    11. eventcategory

      这是什么术语

    12. event category

      这是什么?

    13. The signal yield is obtained with an unbinned extendedmaximum-likelihood fit to the three variables Mbc, ∆E,and O′NN.

      unbinned extended maximum-likelihood fit 这是什么?

    14. We apply a loose criterionONN > −0.5 to reduce the continuum background

      使用 NN 剪去背景

    15. B thrust axis

      thrust 轴是什么东西

    16. observables based on event topology

      这是什么东西

    17. misreconstructed

      错误重建具体是哪里错误了

    18. χ2 value

      此处的\(\chi^2\)如何计算

    19. B-vertex fit

      顶点拟合是指什么?前面的最小接近距离?

    20. In the case of multiple B candidates, wechoose the candidate with the lowest χ2 value for theaforementioned B-vertex fit.

      抽取合适的 \(B meson\)

    21. The Mbcrequirement corresponds to approximately (−16σ, +3σ)in resolution around the nominal B mass [12], and the∆E requirement denotes a ±10σ window around zero

      没看懂,这里的对应是什么

    22. further study

      进一步研究什么?

    23. a maximum-likelihood fi

      这是什么?为什么这么做?怎么实现?

    24. We perform a fit for each B candidate, constrainingits decay products to originate from a common vertex

      common vertex是哪一个?B meson 衰变?

    25. the beam-energy-constrained mass

      这是什么东西?

    26. distance of closest approach

      这是什么?

    27. candidates

      如何理解 candidate?就是衰变产物?

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