<div dir="ltr">Sorry for the spam -- message was rejected by the blackmax project server for oversized email. I have replaced the attachments with links.<div><br></div><div>---------------------------------------------------------</div><div><span style="font-size:12.8px">Dear BlackMax authors and Prof. Gingrich,</span><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">As a member of the CMS blackhole analysis team, I would like to seek your advice on some interesting observation while using BlackMax to calculate string ball cross sections.</div><div style="font-size:12.8px">We observe that, the string ball cross section remained roughly constant despite the fall of parton distribution function as minimum black hole mass increases. </div><div style="font-size:12.8px">More specifically, we studied parameter set 1 [1] in details and obtained the following cross sections:</div><div style="font-size:12.8px">minimum BH/SB mass = 6 TeV cross section = 7.41 E-02 pb</div><div style="font-size:12.8px">minimum BH/SB mass = 7 TeV cross section = 6.90 E-02 pb<br></div><div style="font-size:12.8px">Whereas for parameter set 2 [3], the cross section drops by an order of magnitude for the same increase in minMBH. </div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">For both parameter set 1 and 2, the parton-level cross section should remain constant as M_s/gs < M_SB < M_s/gs^2. To see this works in BlackMax, I plotted [3] the parton-level cross section factor pi*(r_max-r_min) as the code samples different M_BH during the calculation for cross section. Interestingly, if we use minMBH=6TeV in parameter set 1 as input (Red dots), the factor decreases up to 2 orders of magnitude for same M_BH below the SB-BH transition(8TeV) and for minMBH=7TeV(Blue dots), there is no such decrease. I think this effect compensated the drop of PDF and kept the cross section constant when we go from 6 TeV to 7 TeV.</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Could you explain what is the physical reason for the variation of parton-level cross section for given M_BH? And more interestingly, why would the behaviour be different for minMBH =6 and 7TeV? For your reference, I also attach the same plot [4] calculated with a different parameter set [3].</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">For your ease of reproducing the problem, I have attached the input parameter files to produce the plot [5],[6] and I am using BlackMax-2.02. Please let me know if you need any further information on the conditions for producing these results.</div><div style="font-size:12.8px">Thanks a lot for your help.</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Best,</div><div style="font-size:12.8px">Martin</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"> </div><div style="font-size:12.8px"><div style="font-size:12.8px"><div style="font-size:small"><div style="font-size:12.8px">[1] Parameter set 1 (SB_EXTRA4): M_D=2.38 TeV, M_s= 2 TeV, gs=0.5 (M_s/gs^2 = 8 TeV)</div></div></div></div><div style="font-size:12.8px"><span style="font-size:12.8px">[2] BM_SB_EXTRA4_xsec_parton.pdf</span><br></div><div><span style="font-size:12.8px"><a href="https://drive.google.com/open?id=0B-LlizIXYvNVcVBtZlJCMXI1R3RaU2JtZlZBNHpscmVGZ3A0">https://drive.google.com/open?id=0B-LlizIXYvNVcVBtZlJCMXI1R3RaU2JtZlZBNHpscmVGZ3A0</a></span><br></div><div style="font-size:12.8px"><span style="font-size:12.8px"><br></span></div><div style="font-size:12.8px"><div style="font-size:12.8px">[3] Parameter set 2 (SB_EXTRA2): M_D=1.49 TeV, M_s=1.1 TeV, gs=0.3 (M_s/gs^2 ~12.2 TeV)</div></div><div style="font-size:12.8px"><span style="font-size:12.8px">[4] BM_SB_EXTRA2_xsec_parton.pdf</span><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px"><a href="https://drive.google.com/open?id=0B-LlizIXYvNVLUpCdnVFRVNpVzFRYVMzMWxQT2xad1lvS05V">https://drive.google.com/open?id=0B-LlizIXYvNVLUpCdnVFRVNpVzFRYVMzMWxQT2xad1lvS05V</a></span><br></div><div style="font-size:12.8px"><span style="font-size:12.8px"><br></span></div><div style="font-size:12.8px"><span style="font-size:12.8px">[5] SB_EXTRA4_MBH6000_n6_custom.<wbr>txt</span></div><div><span style="font-size:12.8px"><a href="https://drive.google.com/file/d/0B-LlizIXYvNVT2p2bU5SamdEbHhobjdYRG93U052UXNUWXNR/view?usp=sharing">https://drive.google.com/file/d/0B-LlizIXYvNVT2p2bU5SamdEbHhobjdYRG93U052UXNUWXNR/view?usp=sharing</a></span><br></div><div style="font-size:12.8px"><span style="font-size:12.8px">[6] </span><span style="font-size:12.8px">SB_EXTRA4_MBH7000_n6_<wbr>custom.txt</span></div></div><div><span style="font-size:12.8px"><a href="https://drive.google.com/file/d/0B-LlizIXYvNVLXVNSlZpd0pxOG92ejJUYmJVN3E3NmlORGNB/view?usp=sharing">https://drive.google.com/file/d/0B-LlizIXYvNVLXVNSlZpd0pxOG92ejJUYmJVN3E3NmlORGNB/view?usp=sharing</a></span><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Sep 12, 2016 at 2:49 AM, Kwok, Martin <span dir="ltr"><<a href="mailto:ka_hei_martin_kwok@brown.edu" target="_blank">ka_hei_martin_kwok@brown.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear BlackMax authors and Prof. Gingrich,<div><br></div><div>As a member of the CMS blackhole analysis team, I would like to seek your advice on some interesting observation while using BlackMax to calculate string ball cross sections.</div><div>We observe that, the string ball cross section remained roughly constant despite the fall of parton distribution function as minimum black hole mass increases. </div><div>More specifically, we studied parameter set 1 [1] in details and obtained the following cross sections:</div><div>minimum BH/SB mass = 6 TeV cross section = 7.41 E-02 pb</div><div>minimum BH/SB mass = 7 TeV cross section = 6.90 E-02 pb<br></div><div>Whereas for parameter set 2 [3], the cross section drops by an order of magnitude for the same increase in minMBH. </div><div><br></div><div>For both parameter set 1 and 2, the parton-level cross section should remain constant as M_s/gs < M_SB < M_s/gs^2. To see this works in BlackMax, I plotted [3] the parton-level cross section factor pi*(r_max-r_min) as the code samples different M_BH during the calculation for cross section. Interestingly, if we use minMBH=6TeV in parameter set 1 as input (Red dots), the factor decreases up to 2 orders of magnitude for same M_BH below the SB-BH transition(8TeV) and for minMBH=7TeV(Blue dots), there is no such decrease. I think this effect compensated the drop of PDF and kept the cross section constant when we go from 6 TeV to 7 TeV.</div><div><br></div><div>Could you explain what is the physical reason for the variation of parton-level cross section for given M_BH? And more interestingly, why would the behaviour be different for minMBH =6 and 7TeV? For your reference, I also attach the same plot [4] calculated with a different parameter set [3].</div><div><br></div><div>For your ease of reproducing the problem, I have attached the input parameter files to produce the plot [5],[6] and I am using BlackMax-2.02. Please let me know if you need any further information on the conditions for producing these results.</div><div>Thanks a lot for your help.</div><div><br></div><div>Best,</div><div>Martin</div><div><br></div><div> </div><div><div><div style="font-size:12.8px"><div style="font-size:small"><div style="font-size:12.8px">[1] Parameter set 1 (SB_EXTRA4): M_D=2.38 TeV, M_s= 2 TeV, gs=0.5 (M_s/gs^2 = 8 TeV)</div></div></div></div></div><div><span style="font-size:12.8px">[2] BM_SB_EXTRA4_xsec_parton.pdf</span><br></div><div><span style="font-size:12.8px"><br></span></div><div><div style="font-size:12.8px">[3] Parameter set 2 (SB_EXTRA2): M_D=1.49 TeV, M_s=1.1 TeV, gs=0.3 (M_s/gs^2 ~12.2 TeV)</div></div><div><span style="font-size:12.8px">[4] BM_SB_EXTRA2_xsec_parton.pdf</span><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">[5] SB_EXTRA4_MBH6000_n6_custom.<wbr>txt</span></div><div><span style="font-size:12.8px">[6] </span><span style="font-size:12.8px">SB_EXTRA4_MBH7000_n6_<wbr>custom.txt</span></div></div> </blockquote></div><br></div>