Running the CERN LHCf experiment and validating nuclear interaction models at ultra high energies

运行 CERN LHCf 实验并验证超高能量下的核相互作用模型

• 批准号: 20340058
• 负责人: KASAHARA Katsuaki
• 金额: $ 12.15万
• 依托单位: Waseda University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2008
• 资助国家: 日本
• 起止时间: 2008 至 2010
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-20340058/
• 关键词: 超高エネルギー宇宙線; LHC加速器; ハドロン相互作用; モンテカルロ; 空気シャワー; 宇宙物理; GZKカットオフ; CERN LHC; 多重発生; 各相互作用モデル

LHCf is a dedicated experiment to observe the spectrum of photons and neutrons produced in the very forward region of collisions at CERN LHC of which energy is comparable to the ultra-high energy cosmic rays (UHECR). The purpose is to validate nuclear interaction models used in the Monte-Carlo (MC) simulations for cosmic-ray experiments, and thus to help clarify the mystery of UHECR.LHCf successfully observed the 450 GeV+450 GeV collisions in the end of 2009 and also 3.5 TeV+3.5 TeV collisions in 2010. The energy is equivalent to the laboratory energy of 4.3・10^<14> eV and 2.6・10^<16> eV, respectively. We examined MC models, DPMJET(v3.04), PYTHIA(v8.145), QGSJET II(v03), SIBYLL(v2.1) and EPOS(v1.99). The spectrum in this completely unexplored region was found not completely far way from our expectation, but these models cannot fit the experimental data in a satisfactory way. The photon spectrum is softer than many MC models while hadrons show a harder spectrum. If we consider the pseudo-rapidity (η) distribution in the central region, obtained by other LHC experiments (ATLAS and CMS), together with our data, we may say all interaction models breakdown in the LHC energy region. DPMJET is a very good model in the low energy region but its photon spectrum is much harder than the LHCf data and theηdistribution suddenly breakdowns at LHC energies. PYTHIA, though tuned to fit the LHCηdistribution, shows a similar photon spectrum as DPMJET.These facts indicate that we need to explore the highest energy LHC collisions expected in a few years to clarify the breakdown tendency and to validate the models, and also that it is important to construct a new interaction model.

LHCf是一项专门的实验，用于观察欧洲核子研究中心（CERN）大型强子对撞机（LHC）碰撞前段产生的光子和中子的光谱，其能量可与超高能宇宙射线（UHECR）相媲美。目的是验证用于宇宙射线实验的蒙特卡罗（MC）模拟中的核相互作用模型，从而帮助澄清UHECR的奥秘。LHCf在2009年底成功观测到450 GeV+450 GeV碰撞，在2010年也成功观测到3.5 TeV+3.5 TeV碰撞。该能量分别相当于4.3·10^<14> eV和2.6·10^<16> eV的实验室能量。我们研究了MC模型DPMJET（v3.04）、PYTHIA（v8.145）、QGSJET II（v03）、SIBYLL（v2.1）和EPOS（v1.99）。在这个完全未开发的区域发现的光谱与我们的预期相差不大，但这些模型不能以令人满意的方式拟合实验数据。光子光谱比许多MC模型更软，而强子则显示出更硬的光谱。如果我们考虑其他大型强子对撞机实验（ATLAS和CMS）获得的中心区域的伪快度（η）分布，并结合我们的数据，我们可以说所有的相互作用模型在大型强子对撞机的能量区域都崩溃了。DPMJET在低能区是一个很好的模型，但它的光子谱比LHCf数据要困难得多，而且在LHC能量下η分布会突然崩溃。PYTHIA虽然经过调整以适应lhcη分布，但显示出与DPMJET相似的光子光谱。这些事实表明，我们需要探索预计在几年内最高能量的LHC碰撞，以澄清击穿趋势并验证模型，并且构建新的相互作用模型也很重要。

项目成果

LHCf : a Calibration Tool for Cosmic Ray Physics at LHC

LHCf：LHC 宇宙射线物理校准工具

• 发表时间: 2009
• 期刊: Journal of Physical Society of Japan, 78 Suppl A
• 作者: O. Adriani;L. Bonechi;M. Bongi;G. Castellini;R. D'Alessandro;D.A. Faus;K. Fukui;M. Haguenauer;Y. Itow;K. Kasahara;D. Macina;T. Mase;K. Masuda;Y. Matsubara;H. Menjo;M. Mizuishi;Y. Muraki;P. Papini;A.L. Perrot;S. Ricciarini;T. Sako;Y. S
• 通讯作者: Y. S

LHCf実験におけるLPM効果の検証-MCによる解析方法の検討

LHCf实验中LPM效果的验证-使用MC的分析方法的考虑

• 发表时间: 2010
• 作者: B. Adeva;M. Chiba(10番目);M. Kobayashi(34番目);K. Okada(52番目);F. Takeutchi(69番目);さこ隆
• 通讯作者: さこ隆

10^20から10^6eVに渡る空気シャワーシ・シミュレーション

10^20 至 10^6eV 的风淋模拟

• 发表时间: 2010
• 作者: S. Odaka;Y. Kurihara;Tatsuo Kobayashi;M.Ishiwata;笠原克昌
• 通讯作者: 笠原克昌

LHCf- un esperimento per la fisica dei raggi cosmici ad LHC

LHCf- LHC 宇宙实验

• 发表时间: 2009
• 作者: K.Itoh;H.Nakaya;Y.Kawakami;T.Fukatsu;H.Itoh. S.Iwai;T.Sasaki;S.Saito;Y.Naito;O.Adriani
• 通讯作者: O.Adriani

Recent results from LHCf

• DOI: 10.1051/epjconf/20159908004
• 发表时间: 2013
• 作者: H. Menjo;O. Adriani;E. Berti;L. Bonechi;M. Bongi;G. Castellini;R. D’Alessandro;M. Prete;M. Haguenauer;Y. Itow;K. Kasahara;K. Kawade;Y. Makino;K. Masuda;E. Matsubayashi;G. Mitsuka;Y. Muraki;P. Papini;A. Perrot;D. Pfeiffer;S. Ricciarini;T. Sako;Y. Shimizu;Y. Sugiura;Tatsuo Suzuki;T. Tamura;A. Tiberio;S. Torii;A. Tricomi;W. Turner;Q. Zhou